Get the games for whatever console you have more friends playing on that system.
I love PS3 Madden because of the wonderful community but i wish i had a 360 for NBA 2k series because i feel the ps3 community sucks ass for it.
Thats exactly how I feel and should be the common theme of this thread. No doubt the people that get everything for the 360 aside from Ps3 exclusives prefer XBL and its community. Likewise for those that go with the Ps3 instead.
Me I don't play online much so Live has no value for me, and the only good games for the system are shooters and their isn't much of a variety.
Sports is a wash I say, since I get Basketball games on the 360 while Football and Baseball I get on my Ps3. All in all just purchase games for the system most of your friends are on to have the most fun.