While I'm all for great subs, and I own both HSU and Outlaw and have been happy with both, I think several of the previous reccos that have the OP spending half of his 2000 dollar budget on bass are off-the-mark. If it were me, I'd check out the 'budget subwoofer' thread on this forum and find out what's the consensus on the lowest, loudest sub for 300. (BIC PL200 perhaps?) With my remaining 1700, I'd buy Ascend 340 SE for mains and center ("mini-towers, between tower and bookshelf, solid down to 60 hz) and Ascend CMB 170 rears, a Sony PS3 as a source and a decent Denon, Onkyo, or Marantz 100-120 wpc av receiver with the features you want and pre-outs so that when I saved enough money to buy a great sounding 200 wpc power amp, I could add it to the system at a later time.
IMO, the Ascend CMT speakers offer absolutely incredible bang for the buck. And while bass is definitely important for HT, you can always add a second sub later to get more output. Speakers need to be replaced if you want to upgrade, so IMO its more important to get the speakers right in the beginning.
Finally, don't be scared of buying used. There are some incredible deals on Audiogon, and the market is fairly well regulated. I've bought there on several occasions, and my products have always been as described. If you buy used, 2000 can really go a long way. You might very well be able to find the subs that the other posters are telling you to get at the 300 price point.