If your main listening source will be movies and your room isn't very large (less than 3,000+ cu. ft), I'd suggest sticking with a dipole, bipole or multipole speaker of some sort for surrounds. If you do have a large room and multichannel music listening (DVD-A, SACD, DTS 5.1 music, etc.) is the predominant source of your listening, you may want to timbre match your surounds with some of the SVS bookshelfs as suggested. While I do multichannel music listening and stereo/matrixed stereo listening (PLIIx Music), I still find a good set of dipole/bipole/multipoles do an excellent job with creating an enveloping soundfield while still allowing for smooth panning from fronts to rears without creating obvious differences in timbre.
The Cambridge SoundWorks surrounds are decent surrounds for the money (in fact, I'm using them in my secondary HT setup), particularly if you can go with the white ones from their outlet store, they're hugely discounted right now,
here's the link for them.
While some of the Klipsch surrounds would a decent job, they're rather bulky and expensive for their performance. From my experience with a good friend's Klipsch Reference surrounds, they're very efficient and throw a good soundfield, but with music, they aren't terribly appealing (my personal preference, obviously). This, coupled with their cost and footprint/size, would put them lower on the list of my suggestions. I can't imagine the lower end Klipsch surrounds perform any better, so I would be hesitant to suggest them.
One recent deal I've seen is for some Polk Audio FXi3 surrounds that look like they're being cleared out.
Here's a link to Newegg that's selling them for $149/pr., I think some other places are selling them discounted recently as well. I'm not personally familiar with them, however they seem to have decent specs, positive feedback from users and are fairly well constructed. Similar to the Cambridge SoundWorks surrounds I'd suggested above, the only drawback is they're white in color, so if that's a no-go, than that rules it out fairly quickly.
As for the Emotiva ERD-1s, these surrounds would be hard to beat for the money whether the source is mostly music or movies. They're highly configurable, easy to mount, can't take goobs of power and are one of the best performing surrounds I've had, which are quite a few priced anywhere between $200-$600 a pair, including CSW's S300s, Boston Acoustics VRXs as well as Axiom Audio's QS8s. I bought them when they were a bit more than $300 and they were an excellent deal at that price, so for $250/pr., they're the deal of deals for surrounds, IMHO.
Whether you go with direct radiating or multipole surrounds, I wouldn't put a ton of emphasis on timbre matching, get the best surrounds that will fit your application, preferences (sonically and aesthetically) and ultimately what you can afford...
-TD
