10. Might & Magic 2: Gates to another world. (DOS 3.3) I finished that game several times, and even managed to kill the Megadragon.
9. Might & Magic 3: Isles of Terra (DOS 3.3) I also played this one several times.
8. Wizardry VII: Crusaders of the Dark Savant - easily the best of the Wizardry series
7. Icewind Dale + Heart of Winter expansion - I liked this Infinity engine game more than Baldur's Gate, and that's saying something because Baldur's Gate is incredible.
6. Diablo. What more is there to say about this classic?
5. Mass Effect - I finished this one several times with different classes. It's just epic. ME2 was nowhere near the quality of this game. I haven't gotten around to playing ME3, yet.
4. Dragon Age: Origins - Incredible game and HUGE. The only part I didn't like was the Fade, and there was a mod that allowed you to avoid that incredibly-annoying-after-the-first-time-through-it part.
3. Diablo 2 + LoD expansion - How on earth could I make a list that doesn't include this?
2. Sacred + Underworld expansion - I LOVED Sacred. It, to me, is simply a better game than even Diablo 2.
1. Star Wars: Knights of the Old Republic. Pretty much the pinnacle of gaming, imho. Considering that you can also play it in wide screen with a resolution hack now, it is tremendous fun even on a lower end laptop.
ETA: I can't believe I forgot Final Fantasy. My GOD. I think I blew an entire summer on that one. It has been years since I played it, but I played it so much that I can pretty much remember every single thing you can do in it LOL. I played with a BB/RM/WM/BM, F/BB/TF/WM, BB/BB/BM/WM (easily the best combination there is - it starts off slow until the BBs can start using punches, but once it takes off, it's unbeatable).