Wii is my favourite due to the IR pointer, and 1st party games. Motion sensitivity has alot of potential.
I'm buying a DS when I get some money, for the touch and dual screen, as well as 1st party games.
I'll buy a PS3 eventually, to play RE5, FFXIII and MGS4
360 has few games that appeal to me
PSP, i couldnt justify buying it simply to play Patapon