Bioware - Mass Effect, Neverwinter Nights, Dragon Age Origins (what I've seen so far), Knights of the Old Republic, Baldur's Gate 2, their work on The Witcher and oversight (I think) on NWN2.
Blizzard made the game I've played the most, and Bethesda made one of my favourite fantasy games (Oblivion), but Bioware have consistently given me enjoyment with their games and I'm probably a "life customer".