In no particular order:

1. Diablo2.
2. Heroes of might and magic 3
3. WoW
4. Starcraft
5. Counter-Strike
6. Quake3
7. Entire C&C Series
8. Warcraft3 TD
9. Might and magic 7,8,9 & Dark messiah (i know i know but i like it!)
10. Wolfenstein ET