First to get out of the way if you are truly dedicated to your two channel music do not combine it with surround system. Keep them independent of each other. REL is the best in your price range!
I need a subwoofer recomendation
I've got a couple KEF Q900's powered by a Yaquin tube amp and primarily play records. I'm looking for a sub that might also work for movies down the road if I ever put together a surround system. The sub needs to have speaker level inputs and I'm looking to spend $500-$700. My room is 20x20 with a vaulted ceiling and hard surfaces. I've been looking at the HSU VTF-2 Mk5 and the SVS SB-1000 and SB-1000 pro. Is there anything else I should be considering?
On a separate note, if I head down the surround system path, I was thinking of starting with the KEF Q250 or Q650 center speaker to start. Is there something other than KEF I should be looking at that would be a decent match with my Q900's?