Take a look at the PSB B-25's or the Boston Acoustics CS-26's. These are in your budget and are great for the price. The PSB is a larger bookshelf and may be better suited for that size room. The Infinity Primus 162 is another decent budget bookshlf. I bought a pair of older 160's for my daughter and it has pretty good sound but you will want to use a sub with it for sure. You will probably want a sub with that size room. There are plenty on inexpensive subs that will fit the bill. Are you absolutely set on bookshelfs? There are a couple of good budget floor standers.

http://www.audioadvisor.com/prodinfo.asp?number=PBIMB25

http://www.audioadvisor.com/prodinfo.asp?number=BOCS26

http://www.bhphotovideo.com/bnh/cont...A=endecaSearch

Floor standers- http://www.audioadvisor.com/prodinfo.asp?number=ENC300

http://www.audioadvisor.com/prodinfo.asp?number=ATLS300