Proving to not be a one week wonder, Gears of War is still the top dog on the Xbox LIVE activity charts provided by Major Nelson:

These lists are based on global unique users connected to Xbox Live. If the Xbox 360 list and the original Xbox list were combined, then Gears of War would be the top Xbox Live title.

Xbox 360 Top Live Titles (UU’s)
1 Gears of War
2 Call Of Duty 3
3  SUPERMAN DEMO
4  Small Arms
5  Rainbow Six Vegas MP Demo
6  Madden NFL 07
7  LOST PLANET MP Demo
8  Call of Duty 2
9  Tony Hawk's Project 8 Demo
10  Ghost Recon 3


Top Arcade Titles (Full Versions)
1  Small Arms
2  Contra
3  UNO
4  Defender
5  Ultimate Mortal Kombat 3
6  Street Fighter II' Hyper Fighting
7  Geometry Wars Evolved
8  DOOM
9  PAC-MAN
10 Texas Hold 'em

Original Xbox Top Live Games
1  Halo 2
2  Battlefield 2: MC
3  Madden NFL 07
4  Counter-Strike
5  Call of Duty 3
6  Star Wars: Battlfrnt 2
7  Forza Motorsport
8  Rainbow Six 3 BA
9  Call of Duty 2
10  Ghost Recon 2