Longwalker

All Time Favorite

Conquests of the Longbow: The Legend of Robin Hood -- The best Sierra adventure game ever, on par with MI1 in a lot of ways.
Deus Ex -- There's no reason for you not to play this.
DOOM -- It's Doom. Episode 1 is the best group of levels ever. Ep 2, 3 & (especially) 4 are quite good too.
The Elder Scrolls: Chapter II - Daggerfall -- Really has a lot more depth than later Elder Scrolls releases. Awesome RPG.
Hitman 2: Silent Assassin -- There's just something about this particular game in the series.
Lightspeed -- One of the first PC games I got. Still quite good.
The Secret of Monkey Island -- The best LucasArts adventure game (and thus the best adventure game) ever.
System Shock -- This game is still incredible after 20+ (formerly 10+) years.
Thief: Gold -- Awesome, atmospheric game. Every little bit of it is memorable.
Unreal Tournament -- I'm not a big MP guy, but UT99 got it right.

Atari 8-bit -- Atari 800XL.
Sega Master System -- A surprise pickup to be honest, but it was a steal at the price.
IBM PC / Compatible -- Self-built (from scratch) Intel i7-3930K, up-to-date GeForce, Windows 7 64-bit. Primary system.
IBM PC / Compatible -- Self-built (from scratch) Intel QX9650, GeForce GTX 570, Windows 8.1 64-bit. HTPC.

Nintendo Entertainment System (NES) -- Model #1 (1980s version). Possibly lost while moving in 2002.
Atari Lynx -- Slightly damaged in form of wrecked wall connector, but still operational. Possibly lost while moving in 2002.
Sega Genesis -- Model #3 (latter-day Genesis configuration). Possibly lost while moving in 2002.
ColecoVision -- Possibly lost while moving in 2002.

Sony PlayStation -- Counts for all PS systems.
Apple iMac -- Also includes all Apple hardware if I can avoid it. Arrogant pinheads.
Apple iPhone -- See: iMac
Apple iPod -- See: iMac