With just over a week to go before its official release, Valve's puzzle-shooter sequel Portal 2 is now on top of Steam's weekly top 10 best selling PC game list. Crysis 2 went down to the number 1 spot while Valve's Potato Sack indie sales promotion-ARG project is in the number three spot this week.

The full top 10 list is as follows:

1. Portal 2 - Valve
2. Crysis 2 - Crytek/EA
3. The Potato Sack - Various indie games
4. Total War Shogun 2 - The Creative Assembly/Sega
5. Call of Duty Black Ops First Strike Map Pack - Treyarch/Activision
6. Blood Bowl Legendary Edition - Cyanide Studio/Focus Home Interactive
7. Dungeon Siege III - Obsidian Entertainment/Square Enix
8. Aliens Vs Predator - Rebellion/Sega
9. Rift - Trion Worlds
10. Dragon Age 2 - BioWare/EA