I can't go past a few all-time classics:
Need for Speed 1&2 spent - plenty of hours on that
Baldurs gate series - so much depth and replayability
Mechwarrior mercenaries - just cool
Speedball2 - great in multiplayer
Mega lo Mania - We've nuked them!
AD&D Goldbox series and Buck Rogers too
The Cinemaware series (old one)
Hidden and Dangerous - good atmosphere, but lousy multiplayer
Battlefield 1942 - good multiplayer, but no atmosphere
Return to Zork
Kings Quest 3, Police Quest 1 - Like the non-linear gameplay
Monkey Island 1, 2 & 3
Ghengis Khan 1
Panzer General 3D and Scorched Earth
Their Finest Hour
European Air War
There are a few more addictive titles, but someone else will put them in.
