1. Civilization series
2. Baldurs Gate series
3. SM Alpha Centauri
4. Fallout series
5. Master of Orion 2
6. TES Morrowind
7. HoMM 3 and 5
8. Warcraft III
9. X series (X2 the threat, X3 reunion, generally the same with new possibilities)
10. Daggerfall
P.S. My last word here xD.
Frozen_Vomit: Wow, your list is similar to mine. And I also play the games you listed in yours, they are maybe not the best for me, but... =)