Of course if you are serious about gaming it is the PS3 however if you are going to be just playing party games for fun, Wii. Mario Party ETC. Although PS3 online game play and all of this stuff such as Fat Princess are much better imho for playing with yourself on the weekend... hehe yea I said that.
I've said this before And I'm saying it again, Nintendo makes games for family and kids, Wii is just the perfect example! You looking for all the cool, big boy games, you'll find it on PS3. Enough said.