Here's an unexpectedly
amazing option for surrounds: a pair of Magnepan MMG-W's. $325 pr. with a 60 day money back guarantee.
http://www.magnepan.com/model_MMGWI've had them for close to ten years and they blend seamlessly with the three different front channel speakers I've used in that time. They are great with the high-efficiency Zu's I currently have. I use them primarily for SACD/DVD-A sourced surround music and they are stunningly good, not just for the money, but good period.
The key is to mount them to the ceiling, on either side of the listening position, parallel to the side walls, and tilted back so they fire directly at each ear. Set like this they only hang down about 8" and blend pretty seamlessly with a white'ish ceiling. The sound is diffused everywhere except at the listening area where it is absolutely focused.
Down sides? They have no bass below 80hz and need some bass management if they are going to be pushed hard. Also, being 5 ohms they need an amp or receiver with some current grunt to sound good.
Regardless of what you settle on, you're cheating your system's potential if you don't try these.
Russ