Tetris ?I can hardly remember of anything good and older I played. Well yes pong but it's not awesome.
+1 for Dungeon Keeper
Umm, Oblivion?
Yes, I'm also part of those that loved Oblivion. Obviously it was because I installed like a few hundreds of mods. Some of the biggest and best mods could turn the fail leveling and difficulty system (that still got me hooked like 300 hours with quests and all that crap) into a really passionating game. Furthermore, modders made literally over 9000 new quests, monsters, weapons, armors, spells, npc, or even entire towns. The graphic enhancement mods also were extremely good. Texture packs, wheather mods, day and night effects on chimneys and windows. Trees, buildings, signs, doors, flora... hell, even rocks got modded.
I can say that Oblivion was maintained as a state of the art game for at least 4 years thanks to the mods. As is, it was already good, although some problems became frustrating after a while. But with mods you could effectively get a beautiful game with the liberty of Daggerfall and the quests of Morrowind.
