I have a 2004 NAD T773 flagship receiver that has performed flawlessly and has a "seperates like" amp section and very good 2-channel performance. The T773 can usually be found on the used market around $350.00 to $500.00+. I know a bit more than your budget but superb performance IMO. It is built like a tank and tips the scales at over 52 pounds.
The "lesser" T763 and T753 are just as musical but can be found closer to you budget.
http://www.ebay.com/itm/NAD-T-773-A-V-Surround-Sound-Receiver-FULLY-TESTED-WORKS-100-Superb-Cosmetics-/290726623605?pt=Receivers_Tuners&hash=item43b0a83975
Mid 2000's B&K receiver's like the AVR305, 307, 505, 507 ar all very musical and powerful and built like tanks also.
http://www.ebay.com/itm/B-K-COMPONENTS-LTD-AVR-505-HOME-THEATER-PROCESSOR-RECEIVER-V1-03-WORKS-/150848095262?pt=Receivers_Tuners&hash=item231f3f441e
Bill
The "lesser" T763 and T753 are just as musical but can be found closer to you budget.
http://www.ebay.com/itm/NAD-T-773-A-V-Surround-Sound-Receiver-FULLY-TESTED-WORKS-100-Superb-Cosmetics-/290726623605?pt=Receivers_Tuners&hash=item43b0a83975
Mid 2000's B&K receiver's like the AVR305, 307, 505, 507 ar all very musical and powerful and built like tanks also.
http://www.ebay.com/itm/B-K-COMPONENTS-LTD-AVR-505-HOME-THEATER-PROCESSOR-RECEIVER-V1-03-WORKS-/150848095262?pt=Receivers_Tuners&hash=item231f3f441e
Bill