$1500 is a good budget for most rooms. However, over 6,000 cu.ft. (considered "extreme" by subwoofer standards) places high demands on any subwoofer. Those subs that have been mentioned are really great choices. Since most of your enjoyment comes from music, the Rythmik mentioned may really impress you. You also may want to look at Hsu, PSA and Reaction Audio. All have extremely capable subwoofers as well. PSA just updated their drivers for the "se" versions in their Power-X line and are very musical as well. Reaction Audio's Jeremy is a musician, so I think it's safe to say his subs would handle most any music you could throw at it.
And a few well positioned large throw rugs might take some of the edge off your room acoustics. Draperies are nice as well. You should contact these companies and see what they say.