Holy Frak.
List (First is Best, Last is Worst):
Myst & Riven (Tied)
Freespace 2 Open & Nexus The Jupiter Incident (Tied)
Escape Velocity Nova (with EVC and EVO TC Plug-ins)
Star Wars Knights of the Old Republic
Quake
Quake 2
Quake 4
Doom 3 (w/ RoE Expansion Pack)
Halo
Counter Strike Source (w/ DoD source and HL2 DM)
Quake 3 Arena
Star Wars Galactic Battlegrounds
Star Wars Jedi Knight 2
Star Wars Empire at War
Star Wars Jedi Knight 3
Star Trek Elite Force 2
BTW, this is not all of my Games, just some of my PC games. The rest are either ones I've not played within the last 2 years, or that I've never played for more than 2 minutes before attaching the CD/Disk to my mobile of crappy games.