These lists are based on global unique users connected to Xbox Live or in the case of Arcade, full versions purchased this week. Here are the top 3 for each charts, see the source for the complete top 10 list.
Xbox 360 Top Live Titles
1. Halo 3
2. Call of Duty 4
3. Gears of War
Top Arcade Titles (Full Versions)
1. Sensible World of Soccer
2. Arkadian Warriors
3. Tempest
Original Xbox Top Live Games
1. Halo 2
2. Battlefield 2: Modern Combat
3. Star Wars: Battlefront 2
