I don't have any experience with the equipment that people are saying to use but I wanted to give you my two cents on a sub. I'm using a BIC F12 (12" / 475w max) and it has more than enough umph for the room it is kept in. The room is roughly 1,600 - 1,800 sq ft and has 12 ft ceilings. I'm sure a lot of people will recommend not using this sub but I don't have any issues hearing it, even up on the third floor. Maybe your budget would allow for two of them? Anyway, like I said I'm sure someone will give a reason why they wouldn't be ideal but I thought I'd give you a heads up.
Equipment - 47" Vizio 120hz 1080p SV470XVT - Onkyo TX-NR809 - Pioneer BDP-150 - HTPC, Xbox 360, Wii - Turtle Beach X41 7.1 Headset - Sennheiser RS170 Headphones
Speakers - Polk Audio CS2, Monitor 70's, Monitor 30's, BIC F12 12" Sub
HTPC - Intel Core i3-3220, 8GB DDR3 1600, 560ti 1GB, 7TB of HDD's, LG Bluray