Honestly...if this is a home theater room, you should try and keep them all the same brand and model if possible. This way they are timbre matched.

If you are looking under $300 I highly recommend:
Athena AS-B1 $180 a pair, free shipping at bestbuy.com if you do not like em just return them to your local best buy
Athena AS-B2 $260 a pair, free shipping at bestbuy.com
PSB 2B $260 a pair at yawaonline.com very nice
warfdale diamond $299 pair at audioadvisor.com
Epos els3 $299 pair at audioadvisor.com

or if you want I will be happy to sell you my B&W 601 S2 for $299 and I will pay the shipping (in the 48 states of course) see ya ciscokid1970@hotmail.com