I'd like to play Gears, Forza and Trials on the 360. Maybe I'd try out Halo too. Nothing too important though. If there was one must have game for me I'd buy the console.

Edit: Rayman Legends on the WiiU is a Must Have for me. But I'll get the WiiU some day for sure, it can happen 2014 after a pricecut, when other big Nintendo franchises have been released too.

Go ahead and throw Versus 13 on 360 (if it's not already being made for 360 that is).

I only own a PS3 and since the damn thing mostly just streams movies and music because of the lack of a certain genre, the following games I will be playing in the future on borrowed consoles...

Lost Odyssey
The last remnant
Blue dragon
Infinite Undiscovery

Xenoblade
The last story

and more...

I want Halo on the PS3. If that happens I won't by an xbox. I have all consoles though. :p

Wii: Xenoblade, The Last Story
3DS: Pokemon X/Y
VITA: Gravity Rush, Uncharted: Golden Abyss
360: Mark of the Ninja??? (Whatever that ninja game is from the creators of Shank), but I'm hoping it comes out on PSN.

i would like to play the PS+ games i have for the vita... will eventually buy one but for now i can only wish...
i would like also to play/try most of the xbox 360 exclusives but i will not buy that console...
have no interest in any nintendo game...

right now i am focus on trying to put a end to my backlog.

360 - Halo and Trials HD. Probably a few other downloadable games here and there.

Wii U - ZombiU, Wonderful 101 (depending on reviews), Xenoblade, X project.

3DS - Fire Emblem.

360: Halo Wars, Lost Odyssey, Crackdown.

I would also list: Left 4 Dead 2, Viva Pinata, Fable 3 and Command & Conquer 3 kind of.  I own all these games on PC.  But, if I had a 360, I'd probably buy them again for that because I just prefer gaming on consoles.

Wii-U: Pikmin 3 when it releases.

Xbox 360 - Witcher 2, Forza 4 and Alan Wake (already played the Halo and GoW series)

Wiiu - Zombie U

3DS - Upcoming Pokemon game

PC - Anno 2070 and a lot of other RTS stuff.

Hmm Tales of Graces F, Tales of Xillia, God of War 3 and ascencion, The last of us, Uncharted series, ni no kuni. I am hoping they add backward compatibility to the PS4 so i can get those when/if i get one.