Straight from Major Nelson's Blog....

Xbox 360 Top Live Games
1 Saints Row
2 Madden NFL 07
3 Call of Duty 2
4 Test Drive Unlimited
5 Ghost Recon 3
6 DEAD RISING
7 Oblivion
8 Texas Hold 'em
9 Chromehounds
10 BFMC

Top Arcade Titles (Full Versions)*
1 Texas Hold 'em
2 Hexic HD
3 Street Fighter II' Hyper Fighting
4 UNO
5 Geometry Wars Evolved
6 Time Pilot
7 Scramble
8 PAC-MAN
9 Marble Blast Ultra
10 Bankshot Billiards 2

*This only counts games that are purchased, not demos

Original Xbox Top Live Games
1 Halo 2
2 Battlefield 2: MC
3 Madden NFL 07
4 Counter-Strike
5 Pro Evolution Soccer 5
6 Splinter Cell Chaos
7 Star Wars: Battlfrnt 2
8 Rainbow Six 3 BA
9 Forza Motorsport
10 Ghost Recon 2: SS