As someone with direct experience with the TX-8555, which is now being used to drive a two-channel system in my house, this thing is a beast -- right down to the feel of its ridiculously heavy master volume knob, which feels like it's encased in some kind of thick aluminum, like the hairline-finished front panel. This 100 watt per channel amp rocks especially given the price.
If you look at one of the very long threads which I began in here, asking for stereo receiver or integrated amp recommendations, you will see where I took Anamorphic's advice and went with a TX-8555...the receiver really does sound like a good power amp, and it's what Onkyo is known for -- clean, crisp power. The unit itself is a hefty beast of a unit for the size of its chassis and price; every button and control makes it feel much more expensive than it really is.
I can recommend the 8555.