Who are your favourite development studios ever, and why?

[Jay520]

NintendoPie said:

Jay520 said:
Gonna have to say Valve, Rockstar, Insomniacs, and Gameloft.

Where's Nintendo? I know you adore Mario.

I'm not going to just list Nintendo since it OS a grouping of multiple developers. and I don't feel like researching which specific developers did which specific titles. Besides, I don't like any of Nintendo developers as much as the aforementioned sevelopers.