Going to Antwerp, Amsterdam, Paris! Give Advice?

I'll answer for Paris, as I live there. I think you should definitely see the Jardin des Plantes (botanical garden) and the Museum of Natural History within it: it's nice and quaint and it smells like 19th century science. For art museums, of course, there's the Louvre and Orsay. But just walking and wandering through the streets is a must. Paris is a multi-layered cake of history, you can see bits from many periods: Roman times (arènes de Lutèce), medieval (Notre-Dame cathedral), Renaissance (the Marais district), classical, 19th century, Art Nouveauetc... it's all a matter of preferences. By the way, Versailles is not far away, just hop on a suburban line (RER C, the yellow one) and you're there.

I'd recommend the Rijk's museum in Hamsterdance (Amsterdam). It's a great place to spend a lot of time. The torture museum is also pretty neat. Oh, and there's a Maddame Tussaud's somewhere in town. Normally, when I'm there, I just sort of walk along the canals until I find something neat like a bookstore or a decent bar.

In Antwerp, I don't know. It's a pretty town, but I've not spent much time there.

As for Paris, well... Pere Lachaise cemetery is a great place. Sacre Couer is nice. But, for big fun, I recommend a trip to the top of the Arc de Triomphe to watch the traffic below (it's like watching bumper cars). And then there's the Louvre and the Ferris Wheel... Harry's Bar is a definite stop if you like bloody marys(they were invented there). Oh... And the catacombs! You have got to tour the sewers of Paris. It's freaky fun.

I second everything Cristophe wrote about Paris. It's a great city to experience on foot, so bring a good pair of shoes. Also: get a pass for the mass transit system - the subway and bus network is great.

In Amsterdam, I'd suggest a boat tour on the canals (yes, it's a bit touristy, but it actually is a nice way to see the city). The Rijksmuseum is a great place for art, if you're into that. Finally, find an Indonesian restaurant and eat "rijstafel" (sp?), where you get lots of different dishes, of which some are spicy, and others are even spicier...

As for Antwerp, that's easy: drink Belgian beer. But be careful, because some of them pack a wallop! There are hundreds of them, and go for the smaller, local brands, not the industrial stuff like Stella Artois. I like the Trappist beers like Orval and Chimay. As for culture and sights in Antwerp, I must have missed those...

I love the Pompidou museum.

All I know about Couch Surfing is I've had some nice conversations with people from the site; never tried staying with anyone. But in general, the rule to finding a place to stay that is affordable is to not go places that are like American hotels. Go to the Information Centre that will be near the Gare (look for a red 'i' in a blue circle) and ask them; they'll have a lot of different choices. The reasonable European hotels will seem more like B&B's, and you may still even be able to find one with a shared bath, which is cheaper. (A lot of places have now upgraded to en suite, but it may be a lot like the bath in an RV: a hand-held shower sharing a room with the toilet.)

Don't neglect student hostels: you'll meet lots of interesting people, and they're cheap. That link (to about.com) lists hostels in Amsterdam at $27 and $18 at the top.

In Amsterdam: the Reikmuseum Annex that has Van Gogh. (Which is, in Dutch, pronounced "van koch" by the way.) The Red Light District is different from anything you've ever seen in the US; you might want to wander through it with a group if you're going through at night. Eat at a Rijstaffel ("rice table") and eat Dutch pancakes --- which are served for breakfast lunch and dinner, and come with both sweet and savoury toppings.

For Antwerp: take a bus somewhere interesting, preferably out of Belgium.

If you have time in Amsterdam I would add the Van Gogh Museum . After a few hours in there I felt like my brain was on fire. That was a good excuse for beer, then more beer and rijsttafel.

Have fun!

I usually live in Amsterdam for a few months each year--November and December will be my next stay. Sorry, too late to offer you a couch.

Unlike Paris and Antwerp, there is a delightful lack of cars and trucks in the central city, and generally a very low level of urban street noise as a consequence. It's what a city would be like if you didn't build cities for the sole convenience of automobiles.

I've only couchsurfed a couple of times, both in Tokyo. The first time was superb. My host showed me many amazing places I would never have found on my own and took me to the restaurants and bars not frequented by tourists. It turned into three of the best days of my two month trip.

I've hosted many couchsurfers at my place in Beijing and have met lots of wonderful people. I'm sure that there are couchsurfing squabbles and sometimes it doesn't work out, but I haven't had or heard of any myself. Most important is to check that other people have given your hosts great write-ups. It's no guarantee but it's a pretty good bet.

Even if you don't couchsurf it's a good resource for finding out local information. I get about an e-mail a week asking for tips on things to see in Beijing and often go and meet the people for a coffee even if I'm not hosting them.

Have a great time!

Antwerp: The Plantin-Moretus Museum of Printing. Day-trip to Brussels?

Amsterdam: Cancel Paris and spend more time here. Wander. And definiately the Rijksmuseum.

Paris: Boring, dirty, and disgusting. See Amsterdam.

I'm not a Paris native but I recall a few things on vacation.
The fromageries are a must stop ( cheese shop). As are the charcuteries ( sausages and salami etc) plus of course the boulangerie. You can make yourself some awesome sandwiches. The parking meter attendants are very well dressed, I like their uniforms.
Steak is undercooked to the max...order it "a point" or well done to get it American medium.
De Gaulle airport is a piece of crap. It's from the 70s and looks like it.
I love Orangina soft drinks.

Oooo yes Phil - orangina rocks! it's one of those drinks I only drink on holiday in Europe because it's never really on the menu here in England.
Paris - I'd recommend Pere Lachaise cemetary too, and I've always missed the catacombs when in Paris but they are on my list for next time, the Pompediou Centre is excellent too, and I went to a Rodin museum last time I was there but I have no idea whereabouts it is in Paris? I thoroughly recommend dressing up smartly and going into some of the designer clothes shops though, last time I was there I was with my mum and it was so much fun doing that with her - well I think they took me more seriously because she looked like she might actually be able to buy something!
Antwerp - all I know is the beer - Chimay is good, and they have some excellent fruity beers, which all pack quite a punch!

http://www.chateauversailles.fr/
http://www.chateauversailles.fr/en/ (english)
Go in a saturday or sunday, and you can see the amazing fountains in the Versailles Garden.
Im from Brasil and Im living in Paris.
My blog about France (in portuguese)
http://www.gluon.com.br/franca/

At http://www.math.uni-hamburg.de/spag/ign/exk/paris04.htm you
have some links (yes it is in german, but you read german like
most of usasians, don't you?).

Anyway, to repeat what others already said, here is a short
list (in no specific order) on where you should go while in
this crazy Paris:

Conservatoire des Arts et M�tiers - Musee National de Technique:
never went there but might be nice. It's probably about instruments
rather than direct science, but hey, might be fun.

Palais de la Decouverte: you must go there. It's very nice. Near
the Champs Elysees. Very nice scientific museum.

La Cite des Sciences et de l'Industrie - Parc de la Villette:
you can't miss this one. It's big and covers a lot of sciences.
There is also a planetarium (correct word? Anyway, it's a room
where you watch stars projected on the roof with a guy explaining
stuff, but in french.) (The Palais de la Decouverte has one also,
but I don't know if it will be open when you are in Paris.)

Museum National d'Histoire Naturelle: of course, you can't miss
this one. Especially La grande Galerie de l'Evolution where you
could send a few of your usasians for them to get a chip trip
in truth (but that's not the point).

Near the Museum National d'Histoire Naturelle is the
Jardin des Plantes, a very calm and peacefull place in the
middle of this mad city (hopefully it won't rain when you are
there). A lot of plants.

You also have the Collection de Mineraux of the Jussieu university
which may interest you. You should at least go watch this Jussieu
university, it's probably the biggest in France, even if its
architecture is not very pretty (it was build after the events
of 1968, so it is very probable that they decided to do something
hard to control by crazy students).

And of course the Musee du Louvre, which is the biggest in the
world if I get it correctly (but since I'm a french native, maybe
the local propaganda washed my brain with this idea) and the
musee d'Orsay, with very nice paintings. The Louvre is from
older periods and Orsay from more recent ones (18th and 19th
centuries, with a special emphasizing on Impressionism). Then
if the crappy art of today interests you, you
have the Centre Georges Pompidou (a former president of this
little country).
Take care of your stuff (money, camera, etc.), tourists are
an appreciated target of some bad guys here, especially in the
very touristic parts (champs elysees, tour effeil, montmartre).
If you want you may go to the Bois de Vincennes (woods of
Vincennes) where is the Parc floral de Paris. They have a nice
collection of bonzais (does it exist in english? these are
trees that were manipulated by humans to be very very small,
some kind of torture ; japanese people are recognized for their
mastery of this stuff). Anyway, you will be faced with very old
living creatures, some are several centuries old. You feel
very... mortal in there.
Well, for your 4 days trip, it is too much I guess. And you
also have to do the classical touristic stuff. Some kind of
tricky optimization problem!

Well, for a first comment on a blog at least I get a non-controversial topic.

I worked in Antwerp for about 4 months and since I lived in a hotel, I can speak to the issue of eating out. You should easily be able to find the Groenplaats, the square in the center of town. I don't remember the name of it, but there is a great Italian place there (it was the only place the Italians working for the company ate, if your back is too The Hilton, it is on your right), if you like rotisserie chicken a place just off the square called de Kip that would make for a great casual meal. There is a good Indian place just off the base of a street called de Keyserlei (2nd left from the end if you are facing the train station). It may not be in season, but you can also get great mussels in Antwerp. There was also a great gelato stand on the Groenplaats (since it is less permanent it may be gone). Whatever you do, if you have french fries get the freitz sauce.

Now, the beer. You can hardly go wrong with anything you order. Though, be careful of Duvel or any "triple" labeled beers as they contain the highest alcohol level. If you like a darker beer, one that you will never find on this side of the Atlantic, try a deKoninck.

I'm less familiar with Paris, but the one thing that hasn't been mentioned that seems like a notable omission is the Picasso Museum. http://www.paris.org/Musees/Picasso/

In Antwerpen, apart from the beer and if you like chocolate (and don't care about diets and stuff), find some chocolaterie and taste the pralines, marzapin and the likes. Before even tasting it, endulge yourself just by looking at those small works of art made of chocolate. You'll probably be amazed at how exquisite chocolate can be... all those chocolate wonders would go well with a fine port wine (an old tawny) but that may not be possible in Antwerpen. More info about belgian chocolate here

In Amsterdam, apart from the canals and the museums, if you have time and curiosity, visit some coffee shop (in Holland it's legal to sell marijuana, and it's in the coffee shops that you can buy it, taste cakes made out of it, buy seeds, you name it...), it'll be something a bit different from the usual tourist circuit...

Catacombs should be quite an original visit:
http://en.wikipedia.org/wiki/Catacombs_of_Paris

Alternative art in Paris, squatts may be interesting to visit too (illegal occupancy of empty buildings by artists). An interesting way to discover true art...
http://www.59rivoli.org/newsite/index.htm
http://membres.lycos.fr/squart/
http://www.lesvoutes.org/contact.htm

Most official tourismic buildings are actually boring, expensive, and crowded (even in october), while there are many valuable places to see... Don't hesitate to ask.