Subwoofer choices under 1K . NHT, Def, SVS

Making a plunge into HT, but probably will use my system 50% for music.

Need help with a sub selection..any ideas welcome

I have a big den, over 3000 cubic ft, with NHT 1.5's as the fronts (AC-1 center). Got em on closeout, great but no bass.

Choices:

* NHT SubTwo (b-stock or closeout)....est 700
* SVS (probably the 25-31)....550
* Def Tech's Supercube 1 (pricey)...1100K.

I'm sure there are other choices out there, but wanted to get input. I want decent HT performance, music isn't the only use, but I don't want boom-boom-boom.