But I do agree that when you get demanding speakers, you definitely need a separate power amp to provide the high power that you won't be able to get from a receiver.
I agree with Arthur, I just added a parasound power amp to my setup and I have to say that the difference was not all that noticable. It did sound a bit better, but you have to really listen hard to notice the difference. Also you might get into a ground loop hum problem like I did. I have...