are all amps equal

Yes, Detlof is right about Tvad being right; "No", is the correct answer. Drubin is also right - your friend is wrong.

One could have a system which is not very revealing, or poorly chosen, where differences in amps may not be very obvious, or specific choices may not live up to their potential. It would not be worth the investment, IMO, to seek out a great amp to go with other components that severely compromise that amps performance, or do not allow it to live up to its potential. It would be like putting a 6.2l Hemi in a '71 Ford Pinto. That said, certainly your Usher speakers are very revealing, and are worthy of a good amp (with only that to go on - I'm assuming the rest of your system is of similar quality). The exception might be if you are transforming a system over time, component by component.

Marco

I've found over the years of going back and forth between full-range speakers and speakers that don't deliver the low end (sub 35hz), that, like Grant, I get more overall enjoyment from speakers that make basement deliveries. I do not lean towards specific musical tastes that take advantage of that. I find I've been spoiled by the expectations that it will be there. When the music does not require it I'm not sure whether or not it factors into my enjoyment, but I would guess that it comes more into play than one might think. I'd certainly also agree with Grant's premise that price does not always define quality or lack thereof and wold extend that to any component in a system. I've heard plenty of great monitor speakers that are fun, musical and engaging, but even the best of them leave me wanting of something more. It is a personal choice though, and I am sure there are those who are very satisfied with a more limited range.

If you dampen the volume knob with gum, you have then opened up a NEW gate to Audio my friend.... Everything will be more liquid and real.

It will double your pleasure, and double your fun!