If KG retires, I think Danny takes Pierce aside and tells him that he should probably opt-out. It's going to be a complete rebuild.
PP could get himself one last real nice payday this summer; he's not a max guy, but he could be looking at something like 3 year/$40M. Now, it might not be in PP's best interest to DO that, since the 2011 season's most likely going to be washed out (so take as much as you can in '10 - '11). But, he could get himself paid and play for a team that'll have a better chance of contending. We'll throw his a going away party and cheer for him whenever he comes back, but PP's not going to want to stick around for another complete rebuild.
I don't see KG retiring, though; that's WAY too much money to walk away from, and he's not going to want to retire on this note.