Best Subwoofer for $500?

I'm currently running an all Energy Connoisseur HT, and need a sub. The mains are C-9s, so there is some bass there, but a sub is always a necessary requirement. My room is only 12' X 15' with 12' cathedral ceilings. I have hardwood floors as well. I don't think I need more than a 12" in this room, and may be able to get away with a 10". I'm worrying about overpowering such a small area. What's the best subwoofer to fit my situation?
I have two brand new Pinnacle Digital Sub-100 10"powered subwoofers for sale. These are a sealed box design for tighter bass and should work very nice in your room without being boomy. These subs have gain controls so you don't have to worry about over powering the room. Check out my ad on audiogon under Pinnacle.
These are great subs at a give away price!!! 195.00/ea. I can't believe i still have them.

Robert G. Sprout
DIY, or if you must the 12inch Dayton "Titanic" kit from parts express.
Dayon Audio 10 or 12, put it together in under and hour and it is powerful and tight.
A friend just picked up a Sunfire SuperJR for $600 at
Hsu Research and Adire Rava are two more good choices under $500.
I used an Adire Rava in a room the same size and was extremely happy with the musicality of that sub.
Go to eBay. Type in "Velodyne" in search. Pick yourself up a bargain as I have.