Wow, that's a tough one. My parents had the PC, I had the C64. So my first PC game was probably Battle Chess or Where In the World Is Carmen San Diego or something, but I'd been playing games on the C64 for years prior to that. Man, there were some great games for that thing.
Oh, man, jump kills are a gold mine!
1) "Eww, I've got noob on my boots!"
2) "Hey, thanks for breaking my fall!"
3) "Cause of death: foot-induced face disorder."