My all time favs, starting from the days when I sometimes got to play some archaic games on my dad's working computer...
Grand Prix Circuit (1988)
Red Baron (1990)
Grand Prix 2 (1996)
X-Wing vs TIE Fighter (1997)
>X-Wing and TIE Fighter in XvT engine... XvT was my first contact with this game series. XWA is not as much fun as TIE Fighter. X-Wing was sometimes a bit tricky...
Freespace 2 (1999)
IL-2 Sturmovik [FB+AEP+PF] (2001 ->)
Freespace Open (2002 ->)
>The Babylon Project
Rome: Total War (2004)
What else... some random games and game demos, but none have captured me like these have. Baldur's gate was interesting, but it got boring even though I only got to play it some way through at my cousin's. Also, I've never been a big fan of FPS shooters, though they are fun in multiplayer deathmatch. We used to play HL in our school's computer class sometimes. *Someone* had put it onto the class's net hard drive, and it was also copied to multiple of the actual computers, too... so every time the teachers "deleted" it, it mysteriously returned rather fast.
Some games have triggered my interest but I never got to by them for one or other reason. Those aren't listed here.