10-11-2010, 05:41 PM
Etymotic Research makes some in the ~$10 to ~$15 range that look interesting. They're not completely flat, and appear to drop off a little at the higher frequencies, but they're the only ones that I can find that include the attenuation chart, so it's hard to compare others.
http://www.etymotic.com/ephp/er20.html
http://www.etymotic.com/ephp/er20.html