Check out my system page here. I've had a lot of fun with the Betas in recent years. I just let them go to fund other gear, but can't say enough good about them. Be prepared to invest considerable time getting them set up properly, not just placement but all the adjustments mentioned above.
I tried many amps with the panels and the bass towers. Of all I tried, I think I liked the Bryston 7B monos as best performance/value, and McIntosh tubes up top. A pair of 275's running mono was very nice.
Enjoy!