If it's all about games, then I would recommend the Wii. If you are into Hi-Def movies and Hi-Def gaming then either go PS3 (Blu-Ray bonus) or the XBOX 360.
Myself, I have the Wii and the PS3, and no plans on getting the XBOX. I have a Toshiba A-20 for my HD DVD player (which is the only reason I considered a XBOX).
Like I said, as far as gaming goes. I love the Wii. My wife actually plays it with me. And, one of the best parts is you can go online to the Nintendo store and buy older games and download them to your Wii, original Nintendo (Super Marios Bros, or Donkey Kong for $5 a piece), Super NES, N64, Sega Genesis, Neo Geo, TurboGrafx 16 (I just bought Bonk's Adventure for $6 the other night, haven't played that one in like 15 years)...
the Wii is "fun", it won't blow you away w/amazing visuals or surround sound. It's all about the fun you had playing games the first time at home probably on the original Nintendo (if your my age). Yet, it is re-inventive all over again w/the controller. Bowling is alot of fun. Plus, the Wii is alot cheaper then the other 2.
My bottom line: I love my PS3, and I love my Wii. But, if I am basing my decision only on gaming. I would choose the Nintendo Wii.
Hope that helps.