Five hundred clams doesn't go very far in terms of real quality speakers. Sure, you can run down to Circuit City or Best Buy and get any number of speakers for that money... but would you really want any of them in your home for any length of time? I think not.
Okay, maybe I shouldn't be so harsh. I know some people who have Polk speakers in that price range and they're happy with them. I think you can do better, but they're not bad.
To really give you a solid recommendation I'd need to know more about your situation: what kind of music you listen to? how loud? how big is your room? what type of amp/receiver do you have? But I'll throw out a couple of suggestions anyway just for fun.
You might think about a pair of Axiom m22ti speakers (
www.axiomaudio.com), especially if you like more boisterous music like rock and pop. If you're really into acoustic instruments, vocals, small bands/quartets, folk, etc., and can work with the speakers for best placement then you should check out the Magnepan MMG (
www.magnepan.com).
In either case don't sweat the fact that you have to order them on-line. Both companies offer a money back guarantee.
Speakers you can find at your local dealer might include Warfdale's Diamond series, and Epos. Both brands are receiving rave reviews of late.
Happy hunting, and enjoy the music.
