Blizzard, Harmonix, CCP. I don't really like WoW, but I respect it as a quality achievement. It's just that EVE is my MMO.
I respect CCP for having the courage to make EVE what it is. It will be interesting to see what their next MMO turns out to be...
And yeah, Activision, EA, and Ubisoft are publishers. EA does have some of its own studios though, like the one up in Vancouver. I think they make the BIG games up there. Ubisoft has a lot of in-house development as well.