Link below provides a lot of nice insight on both bi-wiring and bi-amping. From my own perspective I found that I recieved a bigger benefit from upgrading the amplifier and running a bi-wire set up, (two sets of speaker cables) than I did with two amps arranged in a bi-wire vertical bi-amp setup. Results will vary with your system but I'm confident that in most instances the single higher quality amp will deliver the better performance, assuming you are going to invest the same resources into one amplifier than you would into two. Going the one amp route also requires one less set of interconnects. Hope this helps...
http://www.soundstage.com/synergize/synergize031998.htm
