If you can still find one, the Marantz MM9000 (advertised as 5x150, but my owner's manual says 5x170) can be found online for as little as $600-700. I have never found anybody to say a bad word about this unit, so I am not sure why they are available at that price, but I have one and I am very happy eith it. I am using it to drive M60x2, VP100 and M2x2. I have had it so loud I almost couldn't stand it, and I have yet to see any of the lights which indicate imminent clipping come on. Definitely the best bang for your buck in power amps I have seen out there.
"Shoot, a fella could have a pretty good weekend in Vegas with all that stuff"