need recommendations for sub for music

Hi Everyone,
I recently completed my HT set up with a Sunfire HRS. I love it for its power, tight and clean bass and compact size. But I thought I'd get another small used Sunfire (the Junior, for example) to complete my 2-channel mostly music set up in the family room. It has to be small and cannot be placed in a corner, unfortunately.
But I also wonder what other subs are out there to best complement my system. The family room connects to other rooms in a very open floor plan. I have the Denon AVR2808ci receiver and a pair of Paradigm Studio 60s. The set up is mostly for music.
I have a small budget, so I am looking for a used sub on this site.

Thanks for your suggestions
Hsu is an excellent cheaper sub.
After B&W, HSU, Energy, Sunfire and Paradigm my current and still favorite is the Velodyne DD12.
Depends how much you wanna spend. The velodyne dd12 is a nice sub but kinda expensive. A velodyne hgs 12 is a liitle cheaper and is the same sub without the room correction I'm pretty sure. I think that either one of these subs will sound better than the sunfire. If you can afford a jlaudio sub get that. Best sub out there IMHO.
Thanks, folks. I will be able to seriously consider any brand (if second hand) including Velodyne, JL Audio REL or Revel.
I'd appreciate specific models you recommend that are truly musical. Most of my music is from the cable channels. I think I may need something larger than a 12" woofer, though. It is a large area I want to fill. From your responses, I realize I may also need a unit with room correction for sure, so that helps.
The RELs use 10" and work fine. Try to get a Strata or Storm. Stay away from the T series for music. The RELs have a great deal of room adjustment.
jl audio f113.... should be more than enough
Martin Logan makes a nice little 10" sub called the Dynamo. It can be configured to either fire out or down and its sealed, which i would recommend if your room is smallish and/or if you are limited in where you can place the sub.
If you can swing $700-800 you should be able to get a used James EMB-1000. This is a terrific musical sub that will just blend in.

I replace my sunfire true sub mark II with the EMB-1000 and the difference was so obvious....suddently the bass was just a smooth clean extension of my other speakers. The sunfire was always a little boomy and a little muffled. The EMB-1000 is a 10". I then replace the emb-1000 with their 12" emb-1200 just because I found one at an irresistable price. Honestly, there is almost no difference, but that's probably because of my listening preferences.

Admittedly, it's very hard to find a James dealer to listen to these speakers...but I am comfortable recommending them, even if you haven't heard them first....they are that good.
Dogmatix, you need to look at the specs on the JL's. Very powerful and musical. When talking about cable channels and no corner placement you need lots of power and excursion. JL F113, Velodyne DD18 or SVS Ultra 13 minimum for an open floor plan. JL is small and is built to very high standards. Try and demo some of these subs if you can.
Thanks, I will try to demo the suggestions. If the EMB-1000 is a passive sub, I will rule it out since I want to keep things simple for the wife's buy-in.
I previously owned a lower-end Hsu, and did not like the build quality. Perhaps, the higher end jobs are better built and musical, but I will look elsewhere from now on.
I have been impressed with the JLaudio specs. I will demo those as well as the Velodynes. I will look at the SVS, although I thought they are ported and, thus, not ideal for music?
Passive radiator designs can be more difficult, but not impossible, to integrate into a music only system yet they work terrific in an HT environment. Since you have placement restrictions I would suggest using the Velodyne SMS-1 calibration system to equalize the subwoofer to your system and the room.

Musicality in a subwoofer is usually more about proper equalization of the subs overall output than the sub itself.