A few years ago after a very loud concert, we decided to get earplugs. I did some research and bought two pairs of Etymotic ER20 earplugs. The high points were a flat 20db reduction across the audible spectrum and a comfortable design.
I must say they have performed magnificently. We use them at our periodic R.E.M. fan club concerts, and other venues. When we forget them, we suffer. Simple. At one outside concert (Rusted Root at the Minneapolis Zoo) we forgot them, and bought the disposable foam cheapies at the concession for $3. Nowhere near as comfortable, and you can definitely tell the poor audio response – however I bought an extra pair and resold them at the same show for double my cost – any plug is better than none.
They are comfortable for this type of wear – intermittent. If I had to wear them more, I would spring for the custom fit ones – same audio characteristics but molded to your ears.
A must have for any concert goer. We maybe go twice a year, but my ears are worth it.