Here's an idea: Get two of these. The PB12-NSD/2. It's $899, so get two of them for about $1800. It's a great value for the price. One of these will give you about 3 times the impact of the entry lvl SVS sub (which is a darn good sub too!), so economically your getting 3 times the power for only about twice the price, good price /performance ratio. So two of these would be like putting 6 pb10-NSD's in your room. You really have to start spending alot of money to get that kind of raw power. Plus, you get variable tuning to 25, 20 and 16 hz (typical room is 3-5 hz lower, so it's low enough to capture 99% of the audio for DVD playback. Could you get a more powerful SVS sub? Of course, but I think it's the best value for money spent IMO.
However, it is a huge sub, so you'll need to think about placement before getting too of these. Good luck.