I think you can get a Parasound 855 for around $400. It has 85w/ch and will make a nice upgrade. If your budget is set higher, then there are many.
I'm looking for a used 5 channel amp
My problem is limited shelf depth. The shelf is only 16 inches deep. 50 watts a channel should be enough to drive my Cambridge Soundworks front speakers and Klipsh in ceiling rears. I suspect my Onkyo receiver (50 watt) isn't strong enough and hope to get better sound with components. Any suggestions are welcome. I've never owned anything but mass market gear and am not very knowledgeable.