Capcom: If you look back at this generation, starting from the DC, there are few developers that have produced as many great games, Third Strike, MvC2, CvS2, Onimusha, DMC, Maximo, VJ, RE4. Can't wait till Okami gets here. They fell into a slump in 2002 but their directors and producers rallied and made some really great stuff in the latter end of 2003 into 2004 and finally the flood of great games in 2005. Now if only they could get off their asses and give me Street Fighter 4, all would be right with the world.
Sony Development Teams (Naughty Dog, Insomniac, Incog, etc etc.)
These guys really stepped up to the curb this generation. Out of the three hardware makers, Sony's own teams have produced the most variety. What's more, they wrestled away the platformer title that has always, by default, belonged to Nintendo.