I haven't played as many as others here, so keep that in mind.
1. Deus Ex
2. Final Fantasy VI
3. Final Fantasy VII
4. The Elder Scrolls III: Morrowind
5. The Elder Scrolls IV: Oblivion
6. World of Warcraft
7. Shining Force: The Legacy of Great Intention
8. Star Wars: Knights of the Old Republic
9. Castlevania: Symphony of the Night
10. Mass Effect