Not too much to go on here, but considering the quality of speakers you might get for that price range I'd probably start with a good used pre/pro (i.e. Anthem) and used 5-channel amp since they tend to either work or not, and buy the speakers new unless they're local so I could see/hear them first. When you spend a few grand or so on speakers I think they deserve better than a receiver, especially if music is at all a consideration. I agree with above post that center channel speaker is most critical (probably followed by subwoofer by the way), and for that money you should have many good options. Personally, I'd target spending about $3k on the used amp/pre combo and the rest on the best speakers and sub I could find. Happy hunting and best of luck.