Coming from a guy who has played far too many i can give you a top 3 and also a top 3 or close to in each genre!!
Racing:
1. Burnout - Huge, exciting, amazing multiplayer, geat graphics
2. PGR3 - Great release title, proper racer, awesome visuals.
3. Ridge Racer 6 - Pure uninterupted arcade lovelyness
Action/Adventure
1. Tomb Raider Ledgend - A return to form for the busty aristocrat, flipping brilliant!
2. Condemned - Dark, Adult and a real looker. Fantastic.
3. Kameo - Technically a platformer but also a great game, shows off the 360's power with some epic scenes, online co-op is great too.
RPG
1, 2, + 3. The Elder Scrolls IV: Oblivion - Its the only RPG, sure, but Coca-Cola is the only real Coke and it still rocks my socks. Buy this!
FPS:
1. CoD 2 - I did this one on PC but from what ive seen its equal on 360, pure pee-in-your-pants tear-in-your-eye lump-in-your-throat war action.
2. Far Cry: Instincts Predator - Beautiful as ever with added stealth and brutal feral upgrades, also very challenging with great online play and a superb map-maker.
3. Quake 4: Another i did on PC. Opinion with people is mixed on this one but i thought it was an awesome sequel to Q2 one of the best games ever made. Online play is lacking in polish.
Sport:
1. Amped 3 - Im skewed by a love of extreme sports but this was a great snowboard title with a bizzare yet intoxicating story and roll on the floor cut scenes.
2. Top Spin 2 - Good tennis game, great for multiplay but nails on Live! Career becomes repetative and AI is functional rather than good.
2. Fifa RTWC - Actually a pretty poor, but graphics were good and had that "YES GOAL" yelling factor, sequel now out.
XBOX Live! Arcade.
Generally this is very opinion based. For me tho the followuing have offered me the best bang for buck.
UNO: Purely for screaming profanities at yanks down the mic, made some good buddies too
Geometry wars: Pure as the driven snow, classic arcade stuff (sampler can be found in PGR3's garages)
Outpost Kaloki X: Kooky sim-space-station type game, but then i love theme park type games.
Overall Top 3
1. Oblivion - Not perfect but AWESOME
2.TR - Legend - Onloy complaint, too short.
3. Burnout Revenge - annoying at times but pure class with slick EA presentation
See also - NFS: Most Wanted - Great title, doesnt quite get into racing top 3 but worth a look
Hope this helps you spend a few hundred
