I own a pair of B&W 683s. The sound from them is nothing short of astounding for me. I compared to quite a few similar models when auditioning speakers and they blew everything in the same price range away. For me at least. Unfortunately these are well out of your price range, but I was just saying that, for the price, B&Ws are most definitely worth the price of admission.
If you're a fan of classical music, most likely it was recorded with B&W monitors, so you're at least one step closer to the reference setup with B&Ws... though I suppose that doesn't mean much given everything they'd use to record with would outclass just about anything mere mortals can afford...
Anyway, I highly recommend you go an audition any speakers you think you might want, especially if you're willing to drop $600 for a pair. There's some tight competition at the price range from what I saw while I was looking 2 months ago.