360
The 360 controller is heavy.
The first half of the 360's life cycle was great, so many great exclusives that were usually niche, interesting or just plain awesome. Earth Defense Force, Chromerounds, Lost Odyssey and Dark Messiah are just a few examples.
Larger variety of demos in comparison to the other platforms.
It has Fable 2, Gears of War 1, Halo: Reach, Alan Wake, Metro 2033 and Splinter Cell: Conviction.
Wii
It's small.
It has Gamecube support.
It has No More Heroes.
PSP
Nice screen.
Lots of interesting and niche games.
It's heavy.
DS
Pokemon.
Heaps of games, not all of them good, but it does have variety.
Looks cool.
PC
Retail games are cheap.
Bet with Conegamer and AussieGecko that the PS3 will have more exclusives in 2011 than the Wii or 360... or something.