And I love the Wii, my brother has one... its a TON of fun to play. But the lack of "serious" games is going to kill it if Nintendo doesn't get its act together.
I personally am leaning towards a 360. Two reasons, Mass Effect, and the possibility of a Goldeneye port. :D
BUT if you have a decent budget you could probably get both of those for the same price as 1 PS3.
Don't forget though, XBOX Live is pay to play (and they're talk they are trying to make all computer games pay to play btw) but there is the silver account variation.