Right now I'm using an Adcom 555 to drive my mains and another 555 to drive my two subs. I'm currently using a Marantz MA700 on my center and my rears are powered by my Yamaha DSP-A1. When my 950 arrives I'm going to use an HK Citation 22 (just had repaired) to drive the subs, I'll leave the 555 for the mains and move the other 555 to drive the side surrounds. The MA700 will most likely stay on the Center and I'll purchase a new (used) amp for the rear surrounds. I may chuck it all for the 770 when it arrives.
-MikeS-