I would say Kingdom Hearts, although I haven't played 356 or BBS yet. Also, NBA 2K consistently does me proud every year (granted I only started playing at 2K7, but I hear it was good before then as well). I've loved both Diablo's (although after 2 I can't really play 1 anymore, but I don't think that should count as disappointment). Add to that the 2 Knights of the Old Republic games and the 2 Mass Effects and I guess there's my list.