My roommates and I own all three consoles.
And I'm gonna have to go with the PS3.
A lot of people say 360 because it has a much bigger games library. But seriously, a LOT of those games suck. There's maybe a handful worth playing, and usually those are only worth a single play-through.
I don't know what all the hype about Halo is.. The game isn't the greatest. It's fun, sure. But one of the greatest FPS of all time? Not even close.
This is the year for the PS3. There's going to be some amazing releases for it. The online capabilities are also way better then the 360. I hate how Microsoft has you pay for a LIVE account to play online (They're now charging for LIVE accounts on the PC, which is retarded.).
But really, it all comes down to this.
Wii = Party gamer
360 = Casual gamer
PS3 = Serious gamer