After a full week of Xbox Live activity tracking, EA's Battlefield 3 has climbed to second place, snuggled between two titles in the Call of Duty franchise for the week of October 31. Topping the list is Call of Duty: Black Ops, which Activision called "the [number one] best-selling title in dollars in aggregate across all platforms in the U.S. and Europe for each of the first three quarters of 2011," in its fiscal third quarter report.

During its investor relations call yesterday, Activision Publishing boss Eric Hirshberg noted that "remarkably" Black Ops and Modern Warfare 2 remained the top titles "before, during, and after" the launch of its "competitor's products." Despite it only being tracked for five of seven days on Xbox Live following its October 25 launch, Battlefield 3 debuted at third on the Xbox Live Activity List, provided by Xbox Live's director of programming Larry 'Major Nelson' Hryb.

Based on global unique users connected to Xbox Live, Modern Warfare 2 slipped to third place, while the Xbox 360-exclusive shooter Gears of War 3 held its fourth place spot, ahead of EA's FIFA 12.

Of the top twenty titles tracked for the week, four were from the Call of Duty franchise, with Call of Duty 4: Modern Warfare and Call of Duty: World at War maintaining their 11th and 17th place spots, respectively.

With Call of Duty: Modern Warfare 3 now on store shelves, it will be interesting to see how Black Ops will perform going forward and whether Battlefield 3--which my review noted was "the best military-based online shooter I've played this year"--can challenge for top spot.

Xbox 360 Top Live Titles (based on UU’s) -- Week of Oct. 31
• Call of Duty: Black Ops

• Battlefield 3

• Modern Warfare 2

• Gears of War 3

• FIFA 12

• Halo: Reach

• Madden NFL 12

• Batman: Arkham City

• Forza Motorsport 4

• GTA IV

• Call of Duty 4

• NBA 2K12

• FIFA Soccer 11

• Halo 3

• NHL12

• NCAA Football 12

• Call of Duty: WaW

• Red Dead Redemption

• Assassin’s Creed Brotherhood

• Dead Island