1. Wipeout HD - Amazing graphics, great adrenaline-rush racing and Zone mode is unbelievable. Online play is great, especially with Fury, and did I mention those obscenely nice graphics? Have to be seen to be believed, truly. Best on PS3.
2. Uncharted - I was always interested in this once I got a PS3, simply because I was a massive ND fan from Jak n Daxter. The game lives up to their reputation and is a great (if different) experience, a cut above many action-adventure titles. And the graphics are mindblowing. The only problem is, I like the gameplay style so much, it's hard to play other action-adventurers (eg Resi 5) because they just don't feel anywhere near as good.
3. Burnout Paradise - I fully credit EA for giving Criterion time to make their masterpiece, and whilst the free-roaming racing doesn't completely work, it is pretty great, and with Burnout mechanics (awesome speed, handling, takedowns and soundtrack) it still sets the arcade racing standard.
4. GTA IV - Most people hated this, but I loved it. It felt like someone made GTA grow up. A mature narrative which explored serious themes, with realistic gameplay full of neat graphical and gameplay touches. Liberty City never felt so alive.
5. Super Stardust HD - I got this for £1.59 in the recent sale, and boy was it worth that. Addictive and dazzling in equal measure.
6. Prince of Persia - Rented this and found it suprisingly very good. Despite being free roaming it can be quite repetitive, but between the nice visuals (yes, Uncharted spoilt me here too) and the great platforming -not to mention the genuinely involving storyline - I really liked it.
7. Gran Turismo 5 Prologue - Just give me GT5 now. I can't play this any more, it simply makes me too excited/anticipatory.
8. Motorstorm - I've only got 8 PS3 games, ok, and this is the 8th. Bought for a fiver a few months ago, found it rather dull.
EDIT: Wait, this wasn't PS3 only? Why is this here then? :S. This changes everything:
1. Wipeout 3
2. Super Mario Galaxy
3. Wipeout HD
4. Pokemon Gold/Silver
5. Jak 2
6. Worms World Party
7. Gran Turismo 4 (For now...)
8. Amplitude
9. Guitar Hero 3
10. Lma Manager/ Football Manager
