I'm pretty sure I saw your similar post on the speakers forum. I recommended the SVS PB 1000 for a about $500. SVS is great with a 5 year warranty and 45 day in home trial with free shipping. Rythmik would be my second choice with the LV12R at about $600. But they don't have the as good a warranty.
However, that is all assuming you have a moderate size room. If your room has any real size to it then you may have to consider upping your budget and looking at more powerful options. If you can, please let us know the size of you room.