Pinnacle Babyboomer:
http://www.soundandvisionmag.com/speakers/478/bigger-better-bass-page9.htmlThis is what I've been running for 5 or 6 years now. Not earth shattering bass, but very good, very tight.
Why the babyboomer:
It is very small -- 10"x10"x10" - excellent wife-acceptance-factor
It is very small -- makes placement much easier, so less likely to make compromises in sub placement
It is very small -- uses 8" woofers, the lower mass woofers respond quicker, making tighter, less sloppy bass
It is very small -- and to do this it uses two 8" woofers in a bi-polar arrangement, with each driver out of phase with the other. So when one woofer moves outward, the other woofer moves inward. This again allows very fast respond time and also allows the sub to be built in a sealed box, not ported, which makes for a tighter sound.
This sub does ok at home theater, but it excels at music. Meaning, repeating the points above, it is not designed for earth-shattering, huge, rumbling bass like many get for HT. But it is very fast, tight, and musical and it integrates very well with your L-R speakers (again because its design elements make for a fast responsive bass that doesn't start lagging the response of your 2ch speakers).
I just did a quick search to be sure it was still being sold, and came across this place that has it for <$500 new (which is what I paid for mine).
http://www.parkaveelectronics.com/product.asp?id=PINBABYBOOMER&l=sitemapI may have even bought mine from this place. I can't really remember, but the name sounds familiar.