i can't compare the internet direct subs to the klipsch because i haven't listened to them. but i have listened to a few klipsch subs and the better ones were just overpriced for their sound and the worse ones were unlistenable. of course this is all subjective. also you generally don't have to worry about timbre matching subs at all. yes, one sub may sound better with a given system than another but you do not have the same issues as timbre matching the front three speakers.
any of the internet direct companies mentioned make good products. also in your price range and very good values at $300 for either are the Monitor audio ASW100 or PSB Sub series 5i both from
saturdayaudio.com. the differences between the two are not huge. the PSB has a bit more punch and I'd give it the edge for feel it in the gut power or for a movie heavy setup or a larger room. for me i prefer the ASW100. it's a small black cube with plenty of power for a small room like yours as long as you're not trying to set spl records. i like it's slight edge in musicality over the PSB based on comparisons i did over 3 years ago on these same models at higher prices. (i ultimately chose the ML dynamo which happens to be on sale for $470 now.) you should try to listen to something before you buy if you can, just as a reference. if you don't have a good independent audio dealer nearby, the magnolia section at a best buy can be a good alternative.
good luck
Edited by MaxL - 9/7/09 at 10:20pm