No brainer....
www.bgcorp.com
BG pd-6i ($600 per pair MSRP) and the matching PD-LCRi ($500 each MSRP) for your center channel. BG makes an 8" as well, but the bass out of the 6" is unlike any in-wall I have ever, except for the BG 8" heard without going to a multiple driver solution (and even some of those can be weak) or much larger speaker.
The BG in-wall and in-ceiling products are the best I have heard in your price range. And, to be honest, if you spent any more I would still recommend staying with the BG line. I have yet to be anything but blown away. Their in-wall/ceiling speakers are amazing.
I recently did a very broad compairison of in-ceiling/wall speakers. The more I listened, the better the BG's sounded. I tried them in multiple types of wall cavities as well. They just did a great job. Absolutely better than a pair of Triad Gold/4 in-walls that retailed at $1K per pair. It wasn't even close. The treble and mid was excellent, but the bass that the PD-6i put out was unbelievable.
Other brands that these were put up against: Triad, Phase Technology, Boston, RBH, Dayton Audio, Parasound, Proficient, TruAudio, Sonance, PSB, and some others that I can't remember off the top of my head. We tried these out with movies and many many types of music. Nothing sounded better or even came close. The price points of all the speakers varied a lot as did the materials used in the different drivers. Some of the speakers were much more, some were less, and some of the brands like Triad, RBH, & PSB sent us several different models. I really wanted to test everyone from a value stand point. Some of the pairs were around $300 - $400 retail and at twice the price the BG's, to me, were so much better that I would still call them a high value.
A word to the wise.... while the BG's sound great at lower volumes they get better & better with the more power you put to them. I wouldn't recommend using a $300 receiver to power them. $550 - $800 in a Denon or Marantz would be a good value and provide ample power. Anything more would probably go unused in a room your size.
My company is dedicated towards contiuous improvement and every so often I bring in new product to make sure that we offer our customers the absolute best product and value their money can buy. I can honestly tell you that in eight years I have never been so blown away by an in-wall/ceiling product. I have heard A LOT of in-wall/ceiling speakers and the BG line is without peer in my opinion. I feel the same way about the Phase Technology dARTS system, however that's in a completely different league as far as price point goes.
Down side: depending on where you're located at, good luck finding a demo.