For some great reviews of gear, check out http://www.homecinemachoice.com/reviews/

It's european, I think, but they have a lot of the same models we do. The nice thing about these reviews is they test the ACTUAL power output of the amps.

For instance.
-The Pioneer 1015tx is rated for 7x120w. It puts out 130w into two channels, but drops down to 95w for 5 channel. Hard to beat for bang for the buck.
- The Pioneer vsx-d814. Rated for 100w per channel. Actually only puts out 60w. This is pretty common for most low-priced amps. Which is why the 1015tx is such a good deal.
-The HK 330 put out 5x50 and 2x115. Typical of low end stuff.
-The Yamaha 650 (basically the same as the 657) rated for 7x95w. Puts out 2x115w and 5x50w. Quite a step down in power when you go to multichannel.
- Let's throw the Denon 3803 in there even though it's a bit more pricey. It does 2x130w, which is very impressive, but only 5x50w in multichannel! Not what most want to see from an expensive unit like that!
-The Harmon Kardon AVR630 is rated at 7x75w. Another pricey one. It puts out 5x85w, which is better than it's rating.

As you can see, most amp sections put out plenty of power on 2 channels. However, when you get to multi-channel, many drop off a lot. This may not matter to some people, but I'm sure it's info many would like to know.

Have fun looking through the reviews on that site!