I know this is going to sound like heresy on a site like this one, but if you want some real bass, but are willing to sacrifice a bit of finesse, then take a look at the following site's listing for AR speakers.
http://www.accessories4less.com/
Some of the $900 AR floor-standing speakers are discounted to about $400. When you don't have a lot of bucks to spend, but want reasonably full-range sound, you'll have to make some compromises. And before anyone bashes AR, take note that their current speaker line has received some pretty favorable reviews. At the prices listed on "Accessories4less", you want do much better on a pure dollar basis.