List them all!
Here are mine:
XBOX 360:
Just Cause 2 [fun!]
Deadly Premonition [so under-appreciated]
Battlefield Bad Company 2 [beats cod any day]
Forza Motorsport 3 [Goooooood]
Assassins Creed 2 [the first is better]
Crash Of The Titans [not arrived yet]
Alan Wake [A masterpiece!! AAAAHHHHHH!!!!! It's so good!! lol]
Shadowrun [Really great fun! I'm pleasently surprised]
The Darkness [Very good, really underrated. Slightly bioshock-ish]
Dragon Age Origins [Good but OBLIVION IS MUCH BETTER!!!!]
Mass Effect 2 [Brilliant! Not sure if it's as good as ME1 though]
Red Dead Redemption [Utterly awesome. GUN was badass but this really blows it out of the water]
Gears Of War 2 ['tis good. Not necessarily better than Gears 1 though...online is a blast though!]
Avatar Racedrome [It's an indie game. Pretty darn good, I just wish more people would play it online]
Avatar Paintball [A great indie game. Not very good animation and not much in terms of replay value but still... it's great!]

PSP:
Breath Of Fire 3 [One of the best JRPG's I've ever played!]
Super Monkey Ball Adventure [love it!! Got monkey ball 1 and 2. THis is a worthy addition]
Midnight Club LA Remix [So similar to the xbox 360 version, impressive!]
Tekken Dark Ressurection [Im not a fighting fan but its pretty addictive at times]

IPOD TOUCH:
Monkey Island 1 [I accidentally bought MI2 so I bought this afterwards]
Monkey Island 2 [I thought it was monkey island 1. Nevermind, I got 2 great games!]
BattlEternal [t feels a bit incomplete]
Palm Heroes [soo gooood.]
Ravensword [oblivion portable! Except sooo short]
Crusade Of Destiny [Fun but a lot of grinding unfortunately]
Battle Bears [still downloading]
The Sims World Adventures [Really good. If you want a handheld sims, psp has better ones but this is so fun anyway!]
All In One Gamebox [35 games in one, its really worth it!]
Rise Of The Lost Empires [So addictive!! Cossacks meets Heroes Of Might N Magic]
Archetype [Online only but very fun, nice weapons too]
Modern Combat Sandstorm [Not bad at all, well worth the price]
Explore3D [fail]
Brix Builder [hard to get used to but pretty cool]
Aircoaster Builder [Sooo awesome. Like rollercoaster tycoon 3 but without the business but with far more advanced coaster creation.]

PC:
Guild Wars...sort of....I bought it ages ago but only just got an online key thingy now. [wow is much better]
I've not included any free games like Tinker and the billion ipod touch games XD It would take ridiculously long.