Wolfenstein 3D, Doom I & II, SimCity, Master of Orion, X-Wing, Dark Forces, TIE Fighter, Fleet Defender, Transport Tycoon, Betrayal at Krondor, Dune II, Warhammer:Shadow of the Horned Rat, Warcraft I & II & III, Z, Fallout I & II, System Shock I & II, Sea Dogs, Half-Life, Thief I & II, Homeworld, Shogun TW, Medieval TW, Medal of Honor, European Air War, IL2 & IL2:Forgotten Battles, ...
phew... my fingers ache...

Those games really dragged me in as the have this magical "thing", the spark that makes them different from their followers.