Subwoofer for under $1000-new, used, or DIY

I listen to mostly rock and classical. The sub would be for music only- no HT. I have GMA Europas, a Redgum 120 wpc int. amp and Audio Note tube CD player. I like my system very much, but it could use a little more oomph. My room is small (15x12x10). I've never had a sub before.

I have read about Hsu, ACI, SVS, Sunfire, Rel, Def. Tech., Totem, Titanic, Vandersteen, Rava, lots of DIY models, and a lot of others I can't think of at the moment. Frankly, it's all become a blur.

I am not a "bass freak", but do appreciate the low end of the musical spectrum. I won't say size is no object (smaller would be better), but of course sound quality is more important.

If you've owned or even heard any of the above subs (or any other in the price range) I would really appreciate hearing from you. Any comments or advice from my fellow 'goners (hmm..that didn't sound quite right) would be great. Thanks to all in advance.