The ones that did Ico and Shadow of the Colossus have to be my most appreciated devs of this gen, both games completly blew me away in terms of style and quality. Definatley the best in terms of brining a completly new expirience to gaming.
Nintendo on the other hand haven't really done much. The Ds is great and all, but releasing yet ANOTHER Mario port is annoying, along with all the ones released on the GBA, and apart from the Wind Waker (which I really love) they haven't really done anything great. Well, great, but most of the games are just expansions of what they've done before. Same with most of the other devs, it's fine. But to really earn it creating and brand new game/experience is where it's at.
Rockstar made one pretty good game (not that I really like it) and have pretty much just expanded on that. Ooooo bikes! They're (apparently) good games, just as all the Mario games have been good games, but not very definative.