The fantasy role-playing game jumped from number four to pole position in its eighth month on release.
Several titles rose from their chart positions last week, including The Sims 2: Freetime (hitting number two), Civilization IV Complete (three) and Mass Effect (four).
The top ten in full:
1. (4) World Of Warcraft: Battle Chest (Vivendi Games)
2. (5) The Sims 2: Free Time (Electronic Arts)
3. (7) Civilization IV Complete (Take Two)
4. (8) Mass Effect (Electronic Arts)
5. (2) Sins Of A Solar Empire (Kalypso Media)
6. (6) The Sims 2: Double Deluxe (Electronic Arts)
7. (3) Call Of Duty 4: Modern Warfare (Activision)
8. (9) Age Of Conan: Hyborian Adventures (Eidos)
9. (12) Command & Conquer: Tiberium Wars (Electronic Arts)
10. (13) The Sims 2: Bon Voyage (Electronic Arts)
Leisure software charts compiled by Chart Track, (C)2008 ELSPA Ltd