GamesIndustry.biz has PC game sales figures from NPD for the week ending December 13 in the US. The Sims beats out the World of Warcraft, three SKUs to two, but the Wrath of the Lich King expansion for WoW is king:

1. World of Warcraft: Wrath of the Lich King
2. Spore
3. Call of Duty: World at War
4. Left 4 Dead
5. Fallout 3
6. The Sims 2: Double Deluxe
7. The Sims 2: Apartment Life
8. Bejeweled Twist
9. World of Warcraft Battle Chest
10. The Sims 2: Mansion & Garden