Beyond Good and Evil
Head Over Heels
Super Mario World
Final Fantasy 7
GTA: Vice City

Morrowind
Deus Ex
Fallout
Bioshock
Crysis

Today, anyway.

This list changes all the time, but now I'd say:

5. Silent Hill 2
4. Baldur's Gate 2
3. Final Fantasy VI
2. Chrono Cross
1. Chrono Trigger

With Honorable Mentions:

Age of Empires II
M.U.L.E.
Star Wars: Knights of the Old Republic
Super Mario RPG: Legend of the Seven Stars
Zork

Beh.

- NOLF
- Fallout(s)
- Deus Ex
- Morrowind
- Homeworld(s)

and also

- Pirates
- Giants
- Sands of Time
- System Shock 2
- Stalker

oh and also

- medieval total war
- vampires bloodlines
- loom
- silent service
- F19

and also some others

are my top5.

Still so many classic games I have yet to start. 40+ games bought here this past year. If I consider time spent playing....
1. Civilization IV
2. Romance of the Three Kingdoms (Entire Series)
3. Alpha Centari
4. Sim City IV
5. Crusader Kings II
6. Elder Scrolls III Morrowind
7. Might and Magic VI The Mandate of Heaven
8. LOTR Battle for Middle Earth
9. Fallout II
0. Baldur's Gate

I'm trying to figure out what to play next. Baldur's Gate II, Planescape, System Shock, Deus Ex, Age of Wonders, Europa Universalis IV, Expeditions Conquistador...... There is not enough hours in the day. :(

Almost forgot Heroes of Might and Magic Series. IV is the first one I played. I liked it well enough. Reminded me King's Bounty on the Genesis. I think III is better though. Hoping to pick up King's Bounty during the Christmas sale.