Marvelous has put some good stuff on the Wii, but based on some recent comments made by them it sounds like they wanted to support the HD consoles, and are only supporting the Wii because they don't have the resources to make HD games.
Sega has done well, but as Mr. Kahn pointed out, the success they've had with Sonic seems to NOT resonate inside the company. I'm not going to tell them to stop making Sonic for other platforms, or to not try to broaden Sonic's HD audience, but they seem obsessed with HD (see project Needlemoue), and not putting in the effort to also broaden his audience on the Wii.
I don't see many other companies that are pro-Nintendo; Square-Enix, Namco and Capcom each have a major game coming out (Dragon Quest X, Tales of Graces and Monster Hunter Tri), but even those companies highly favor the HD consoles, following a strategy of real games on the HD consoles, while sticking the 2nd rate crap on the Wii.
Picking the most Nintendo-biased third-party is about as pointless as picking the best disease to contract.