Integrated amp under $ 500.

I recommend Rotel RA-1062. Retail for $700, but you should be able to get a used one within your budget.

I have one, and it sounds great. I used it to drive my ProAc monitors.

02-06-09: Bobgates
I still think the Onkyo A-9555 is one of the best integrated amps in this price category.

Me too. At the asking price of $799 it's definitely competitive, but at the street price of $400 (accessories4less.com) to $474 (Amazon w/free shipping), it's a walkaway. I like it better than any similarly-priced Brit-sourced (including Cambridge) integrated below $1500. More speed and clarity better balanced against fullness, bass power, clarity, and extension. I'd take it in a heartbeat over a Rega Brio 3.

Another vote for the Onkyo A-9555. I've had it for a year and a half and have been very happy with it (although the bass could be a bit tighter). To me, it's certainly better than the NAD in the $500 range.

You can buy it at amazon.com for $280

I have thousands of dollars in amps and like this better than all of them. I'm not kidding either.

Harman Kardon HK3490 that is.