Algeria
Stuart Staniford has a terrific piece that offers a little visual clarity about food, energy, unemployment and the Riots in the Middle East and North Africa:
Tunisia is a minnow in the global oil market, Egypt slightly more important. Algeria, however, matters a lot as its oil production is probably close to total demonstrated OPEC spare capacity. Thus serious social instability in Algeria would have major effects on global oil prices. If instability spread to bigger oil producers than that (eg Kuwait or UAE), the effects could be very dramatic.
Presumably, the regimes in those countries…