Arcade:
qbert
galaga
galaxian
pole position (sometime in the early 80's, I used to put the high score on the Pole Position machine at Penn Station's Station Break every day on my way home from work... I guess the real fun was the awe from the kids, since the game actually wasn't all that much fun and was real short).
Atari 400/800:
Star Raiders
Jawbreaker
Breakout
(several other games that I will probably remember the names of once I post this reply... From late 79 to early 84, I worked at and managed a bunch of retail computer stores (4 locations eventually) in Manhatan, NY (DigiByte which then became Computer Center). We sold Atari's and TI99/4A's and C-64's and Cromemco's (anyone remember them?)... in fact, I ran the store's mail-order software business (Software City) for a long time... anyway, I don't remember all that much of the details thru the haze... did eat a LOT of cold pizza at like 2am, tho) Anyway, I played just about all of the games back then, so I could demo them to customers (yeah, right)
Various PC's:
Zork (and most, well, many, other Infocom games... in fact, I should introduce my kids to these... I found an interpreter for them a while back and I have a whole bunch of the games)
IBM-compatible systems:
An old EGA-era game called Sherlock (a puzzle game), pc-hack, some of the Infocom games...
I work at a college and many of the student workers have tried to get me into various games like Starcraft, but I've never really caught on to them... seem too complicated.
Hmmm... I should dig out my old Atari 800... eh, or just the joysticks for it, and use one of the Atari emulators on one of my PC's