1. Mass Effect 2--- This game is going to be aces all around. I still have fond memories of spending late nights with the first game. Hopefully some of the bugs from the first game will be fixed, but either way I look forward to resuming missions as Commander Shepherd once again in January.
2. Alan Wake --- Yes, this game is still scheduled for release. Hopefully the last 5 years in development Limbo make this game worth the wait.
3. Halo 3: ODST -- What teenager/ Master Chief fanboy doesn't know about this game??? Already released, this game sold over 2 million copies in the first couple of weeks so I'm sure its on a lot of X-mas wishlists.
4. Forza Motorsport 3 -- The biggest racing game on the 360 is ready to deliver on Oct. 27th. The early reviews of this game are already pretty darn good, and it looks like not just an awesome racing game, but a great game overall.
5. Fable III --- This game is planned for late 2010, but the franchise fans area already counting down the days.
6. Left 4 Dead 2 -- The first game was a smash hit!!! Loyal players of the first game are gearing up for the sequels' release just before X-mas.
7. Splinter Cell: Conviction -- Sam Fisher is back, and the creators promise something truly amazing. Touted as the 360's answer to Metal Gear, Sam Fisher's exploits have revolutionized how stealth action games are supposed to be.
8. Crackdown 2 -- The GTA clone's first exploit was nothing short of awesome. This sequel should be nothing short of more awesome for fans of gangbanging sandbox games.
9. GTA IV: Ballad of Gay Tony --- Exclusive DLC for GTA IV coming out on October 29th 2009. 'nuff said.
10. Halo: Reach -- I know, a Halo game that isn't first on a list??? Well, I'm not sure what to expect out of this prequel other than I believe it will be awesome. Time will tell.
That's my list of "10 Must Have" games for the 360 I'll post my list for the PS3 soon.