Help with budget 5.1 system for large room

I am moving into a new house shortly and am excited to put together my first HT system. I am starting from the beginning and currently only have the tv taken care of (a Samsung HDTV LCD). I am looking for a 5.1 channel speaker system for around $2000 used or new. The room is about 22 x 15 and is not ideal acoustically (large vaulted ceilings, open floor plan, etc) but will have to work for now. The system will be used for DVDs primarily, but also 2 channel music. Any advice would be greatly appreciated.