2. SiN (forgot this one, it was my favourite for like a year, it came out the same time as half-life, and was therefore mostly overlooked, very good).
3. Grand Theft Auto (the original one).
4. Black and White.
5. Dungeon Keeper.
7. Quake II.
8. Ultima Online. (Haven't played it in a long time).
10. Populous 2: The Beginning.
11. Age of Empires.
14. Frontier: Elite II
15. Tony Hawks 3 (Just a very playable game).