FAVORITE RPG PUBLISHER...
This is tough. Really tough. All time or flavor of the month?
This might surprises some of you: Palladium Books.
Their books have provided me with hours upon hours of entertainment and I don't even play their games.
In fact, I am pretty allergic to their house system.
But I LOVE their stuff.
But honorable mention goes to: Monte Cook Games, Pinnacle Entertainment Group, Atlas Games, Green Ronin, and Wizards of the Coast.