December NPD stats:
Hardware
Nintendo DS -- 2,470,000
Wii -- 1,350,000
Xbox 360 -- 1,260,000
PlayStation 2 -- 1,100,000
PlayStation Portable -- 1,060,000
PlayStation 3 -- 796,600
Games
Software:
1. Call of Duty 4: Modern Warfare (Xbox 360) -- 1,470,000
2. Super Mario Galaxy (Wii) -- 1,400,000
3. Guitar Hero III: Legends of Rock (PlayStation 2) -- 1,250,000
4. Wii Play w/ Remote (Wii) -- 1,080,000
5. Assassin's Creed (Xbox 360) -- 893,700
6. Halo 3 (Xbox 360) -- 742,700
7. Brain Age 2 (Nintendo DS) -- 659,500
8. Madden NFL 08 (PlayStation 2) -- 655,200
9. Guitar Hero III: Legends of Rock (Xbox 360) -- 624,600
10. Mario and Sonic: Olympic Games (Wii) -- 613,000
Source:
http://www.neogaf.com/forum/showthread.php?t=229157