I originally picked up the Etymotic ER-6P, but I was disappointed in them, primarily lack of bass and loudness.
I returned em for the ER-4P's which sound much better to these ears. The plugs n both take some getting used to, but once you get a good seal, they're great. I have zero regrets about spending another $100 on them over the ER-6Ps. Better specs, moresensitivity, HF anbd LF boosts, plus a nice case and a bunch of extra earpads.
Paid $179 several weeks ago at JandR, which still has them at this price.
/Ken