Now who's mixing it up, Mazer?
Nice. I'd seen you talk about the Cadence before, but I didn't know which way you'd go today.
tyreal78, the Daytons get good reviews, and I was just kidding around about Mazer recommending them. Others sure seem to like them, too. There are a number of subs out there in the $200-$300 range. For a room your size, you don't need a behemoth of a sub to do a decent job, IMO. You could also audition some of the "big brand" subs from Best Buy and Circuit City, such as Polk and Infinity. They get a bad rap around here sometimes, but there's plenty of people that like them. The great thing about those is that you can always try them in your room and then take them back if you don't like them.
Mazer wouldn't steer you wrong, though. I know nothing about Cadence, but I'll bet that it's a good sub.