Needless to say, the Legend of Zelda series. The best I've ever seen, along with Earthbound. ^^
I also liked the Spyro trilogy dunno if its the old or the new, I don't really care much, but I did like the games. Other favorite include... hum... ok, all of the Nintendo franchises. Maybe except for the few ones I haven't played, like Metroid, Yoshi series, etc.
Out of the "Nintendo Realm", I liked Sonic Heroes and some PS1 games I don't remember.