In my head I like to think I would be able to find a good sub for $125-200, but this may be wishful thinking. Once I get some recommendations and see what range those fall in, I can then come up with a fitting budget and try to convince my wife. I can't imagine wanting to spend more than $250, so if there isn't a good option in my price range then that would be good to know.
As for my listening, I like all kinds of music (Rock, Jazz, Classical, Country). I'm not going to be throwing any raves, and I don't want to piss off the neighbors. I just want to fill the room with rich sound and thoroughly enjoy my music.
This will be in an open area of our house that contains the living room, kitchen, and dining room in one large space. The overall measurements of this area are 16 wide x 26 deep, with 9 ft ceilings (no vault). The actual living room portion of this is 16 wide x 16 deep. There is also a hallway on one side of the room leading to the front door.
Primarily I would want the additional bass to fill in the lower gaps left by the Atoms, and mainly for my music collection. It doesn't need to shatter the windows or shake the walls, but a little extra punch would be nice for movies. Of course right now I only have the built-in speakers on my Panasonic plasma, so anything is going to be a huge leap forward comparatively.