ok... this may sound a little weird, but there's a free game for the old mac (>OS10) that I would play non-stop. It has full 3d stereo quality sound and addicting as well. If you can find it (its still out there), it's worth the download!
It's called "Maniac" and its a cross between Pacman and Hangman. It sounds pretty lame, but its addicting for those looking for a game that was well-written and looks sharp.
OK I'm OLD!! I used to play Outpost on old Win3.1/DOS. That was a time consuming game of make your new planet habitable to your people both on and underground...
Then with Win95 I really got hooked on Battlezone by Activision. Hover tanks US against the Ruskies ahh those were the days. That was my first real intro to gaming online with a 28.8 MODEM - it was so much more fun to blast PEOPLE!!!
I played some of DOOM3 but it has such high requirements it locks up my PC often so it is very tough to get into.
Now I play the XBOX went thru HALO I & II and now I play lots of NCAA and NFL football - against PEOPLE again too!