Like so many others on here, I was there during the Atari and Amiga years, (ah, my beloved Atari 520STE) the 486 PC and then the first ever Pentium PC. Soooo many memories from games of each era. More recent again, it was the launch of the Playstation 1.
The first that spring to mind from each era that bring back personal memories are:
Atari/Amiga:
Paradroid 90
Flood
Rick Dangerous
Silly Putty
Zool
PC Games:
Lemmings
Worms
Dark Forces
Doom
Playstation:
Wipeout
Destruction Derby
Thrill Kill (never officially released, ahem)
Twisted Metal
Resident Evil
The list goes on, so many to remember.