I have three different family members with a Denon 2112 and all are happy with it. I think its a pretty solid unit with a decent amp section and, best of all, you get MultEQ XT, which will Eq a Sub. Whatever receiver you get, make sure it will Eq the sub, because, IMO, this will have the greatest impact on sound quality. The 2112 also has a pretty nice GUI, even if you don't need networking. Otherwise, look at the 1712 (its a little cheaper, no networking, worse GUI). Call (you have to call) Electronics Expo or J&R and ask for best price, they are both authorized dealers and you can get that unit new in the box for substantially < your $500 budget shipped and probably tax free, depending on where you live.
Edit: I just saw you might want preouts. The 2112 does not have preouts. I am not sure you need them, but if you want them and still want a Denon, you need to get into at least the 3312.