Look into the self-powered KRK Rokit series, whichever would fit your room size and budget. These are very musical speakers, not edgy like many inexpensive monitors. The founder of KRK is an audiophile.
Note that prices are per speaker, so the closest to your budget is the 8" 2-way Powered 8 G2, which is bi-amped with a total of 90 watts rms per cabinet. I've heard 'em and they sound excellent. You can hear them in the pro audio section of any Guitar Center. You may want to bring your own source material to audition or you'll probably be stuck auditioning with obscenely compressed mp3's of dance mixes.
Note that prices are per speaker, so the closest to your budget is the 8" 2-way Powered 8 G2, which is bi-amped with a total of 90 watts rms per cabinet. I've heard 'em and they sound excellent. You can hear them in the pro audio section of any Guitar Center. You may want to bring your own source material to audition or you'll probably be stuck auditioning with obscenely compressed mp3's of dance mixes.