Well there are a lot of great internet direct sub manufactures that can defiantly make your room rumble. HSU, SVS, Outlaw, Rythmic and Power Sound Audio just to name a few. I have a 2100cubic/ft theater that opens up too a 10x10 area and I recently bought dual XS30s for Power Sound audio. They are a sealed sub with two 15" drivers per sub. These things scare the crap out of me for theater use and sound great for music but I mostly bought them for HT use.
What's your budget?