Aside Lucasarts games, I think the ones that got me addicted were Fallout 1 and 2… god I spent lots of hours on those… i even once wiped EVERY npc on the game just for the fun of it :p
Loved Pharaon, dungeon keeper, Darkseed 1 & 2… played loads of fps games… loved most of them… Doom used to scare me a lot when I was a child.
I still play from time Castle of the Winds 1 and 2… if you like roguelikes this one is REALLY good 🙂
Wish I had the time to play that much nowadays :p