Oh jesus.. so many.. but I guess most of all..
Halo 1 (Oh god.. I actually played through the first level again recently and had so much fun; it just feels so much more epic for some reason than any of the sequels ever did to me)
Marathon Series (The story was just so much fun to discover... and the twisting story through-out the games)
Zelda: Ocarina of Time. (Except I want to be able to remember the quickest route for the water temple, because seriously? Fuck the Water Temple. Also, I remember the Kid water temple to be a pain in the ass, too, although not nearly as bad. What the hell? What's up with water levels.)
Halo: ODST. (The first Halo since 1 where I honestly got IMMERSED in the game, and I loved every second of it. I kept waiting to see what happened next.)
Blah, blah.. lots more, but those are what first pop into my head.