I have two pairs of in-wall Polk Audio RC85i for my Surrounds sides and back. They are driven by an Outlaw 7125. They put out a little bit of a hiss if you get too close but, otherwise, I am happy with the arrangement. My main speakers and subwoofer are floor standing - I just couldn't bring myself to mess with the great sound my Polk RTA-12Cs have been giving me for the last 20 years. Like someone else said in this thread already, in-wall is a commitment.

There are also some excellent "on-wall" speakers. I spent some time drooling over some Martin Logan Fresco's before I decided to stick with Polks.