Konami, Capcom sometimes, ATLUS, CAVE, id, and Namco.
As far as indie games and freewares go, I love ZUN, Cactus, Spiegle works (I think I spelt that wrong), and x.x
ALICESOFT. The only company whose games I'll play without being able to read a single word of text. Also Nippon Ichi for Disgaea and everything related to it.
On the other side of the pond, Bethesda is the only company I have any real loyalty to and that's mostly because Oblivion and Fallout 3 have such awesome modding communities. Can't wait for New Vegas to come out, I just hope my laptop has the specs for it.
Do they have to be active? I'd go for Bioware, Rockstar and Looking Glass/Irrational (lots of the same people) for their consistent brilliance. Whatever you think of them and their franchises, particularly of Rockstar, almost every game across the board has a prevailing quality of construction unlike most others.
lol look at these dumbass blizzard, valve, bungie, and square tards.
well, at least blizzard and valve have made some good games, and square did publish Nier (tho the real credit goes to Cavia). yall could at least be a bit more original
rocksteady has only done some weird riot control game and batman arkham asylum but batman was so kickass i hope they go on to make awesome games forever
Tecmo for Fatal Frame & (crap!?...Ninja Gaiden), Capcom (when they don't follow the Oregon Money Trail), Treasure (enjoyed Astro Boy: Omega Factor), old Sega (they used to treat Sonic better), and Nintendo (they things they come up with)
I am going to go with capcom as my number 1, There are just too many classic to choose from,
For others I would go with treasure, SNK, SEGA, and valve. By the way, why have not anyone tried making a high school of the dead mod for L4D 1or2 yet?
Bioware for the masterpiece that is the Mass Effect trilogy (Dragon age also) and Bethesda for the best solo RPGs ever created (TES: Oblivion & morrowind and Fallout 3)