Just my $.02 here, but I'm not a huge fan of the new(er) Harmon/Kardon stuff. Don't get me wrong here, for your price range, I wouldn't rule out H/K, but you'd be better off saving up and buying something a bit nicer.
Also, what do you have planned for speakers? To me, speakers can make or break the system. If you don't have a good pair, you'll need to reconsider your price range.
Or, if you want to keep it cheap, you could always buy some Edirol MA-15Ds. They're $168 on Amazon.com...and they'll do what you want them to. I can't say I've actually heard them, but I've heard good things...