Mark - Since you will be using a Yamaha as a pre-amp I would avoid Parasound, and Adcom since they emphasize the "grain" on the top end on Yammies. Sunfire is an excellent choice along with the ATI mentioned, and I'll throw in B&K to boot for it's warm tube like sound. I'm currently running 7 B&K Reference 220M's in my theater, but also have a 2220, and a pair of ST 125.3's. Matched up with the M60, VP150, and QS4's it is a huge leap from any receiver I have heard. Be sure though to audition any amp from a reputable dealer in your theater first since that will be the only way for sure you will know what to go with.
