At this stage the Wii is the front runner. However at the rate Sony is going that may change. It also helps that the PS3 is also a kick ass Blu-Ray player, something no one else has. Personally though I use the Wii for just a few select games like Mario Kart. I play the rest of my games on the PC because I do not like the limitations/locked down nature of a console compared to a PC.
EDIT: I pick PS3. I might get 1 for just MSG4 (that game looks bad ***)