I'd rather play it on my PS3 because I want to increase the number of people playing it on the PS3 to deflate the 360 fan boys (that means you, CheapyD!).
Hopefully no one has already posted this one:
The "Earl Grey or English Breakfast" Achievement - Kill and teabag a player that has this achievement (killing and teabagging). Kind of like the viral "Assassin" achievement in GRAW.
If this is chosen may I please have CoD4?
I think you should keep the PSP version so you can play it while riding the subway in New York. This way if another rider is rude to you, you could demonstrate why it is a bad reason to wind up the Wombat. In addition, I do not own a PSP or a Wii.
I do have a PS2 which has been suffering...