what I have
Velodyne 10" Subwoofer (DPS-10)
I'm not sure what physical size you are looking for (or what you are looking to spend), but I really like this one for combinations of size, price and quality. I didn't want something that thumped noise, but put out low frequencies with pitch and decent clarity. In today's word, small subs can put out amazing bass and there are some out there for a lot more money that do truly amazing things...I just can't afford them.