Sorry for the repeats! Since this is all-time there will be some current duds...
Nintendo R&D4/EAD/EPD
Squaresoft
Capcom
Konami
Rare
Ubisoft Montpellier
Ubisoft Montreal
LucasArts
BioWare
From Software
Nihon Falcom
Retro Studios
Monolith Soft
Bungie
Insomniac
Sega
Atlus
Platinum
Valve
Team Ico