As Mr. Peabody says a better receiver will likely be more better than a better BDP, however the challenge is defining a better receiver. As one goes up the line on Japanese AVRs they tend to be more feature laden, not necessarily better sounding per se.
For quality sound I would look at brands like Anthem, NAD, Arcam, Pioneer Elite (VSX-60), Integra, Marantz. The first three will likely only meet your price range if you can find something new or refurbished.