If we're referring to old DOS games, I'd say Doom 1 and One Must Fall 2097. There are others that I also remember fondly, but I don't play them over and over. That includes The Lost Vikings, Wolfenstein 3D and Pinball Fantasies. My overall classic favorite game ever though is Street Fighter II Champion Edition, but it never came out on PC. Only the crap SF2 World Warrior came out on PC. It sucked big time, at least until SSF2 Turbo came out. That one was awesome.

Rob Elam was the guy behind OMF2097. After OMF Battlegrounds was released (and was a commercial failure), he kinda disappeared. Kenny Chou, the guy who did the music for OMF2097, once replied to someone who asked what happened to Rob Elam. He said he hasn't been in contact with Rom Elam for a long time. I would love it if the franchise was given a remaster or something. Just a re-release with modern online play is enough for me.