Mummelmann on 08 December 2013
Valve
Blizzard
Nintendo
Obsidian
Black Isle Studio
IO Interactive
Westwood Studios
Bullfrog
Atari
CD Projekt
Naughty Dog
Firaxis
Bioware
Free Radical
Rare
Konami
Namco
Polyphony Digital
Interplay
In not particular order, I would probably put Westwood, Valve and Bioware at the very top.