John Wilkins and I have been at the Edges and Boundaries of Biological Objects workshop here in Salt Lake City for the past few days. John live-blogged some of the talks, so you may want to check his posts out. Lots of interesting stuff was discussed about populations (here and here), the fossil record (here), ecosystems (here and here), system dynamics and boundaries (here and here), DNA bar-coding (here and here), species, rank-free classification, and homology. All in all some really thought-provoking ideas that will take me a good while to digest.
Discussions are likely to continue at the Philosophy of Biology Cafe.