I don't think that I want the bulk of noise-reducing headphones, though.

We've been issued custom-molded musician's earplugs at work (Westone-branded, although Etymotics might have made them), and although they're pretty kickass when new, their perfectly-conforming fit doesn't conform so perfectly as the ear canal changes shape, which it does over time; the original set I got are now uncomfortable & nearly useless.

I've used quite a few foam plugs in various situations (rifle range, pistol range doubled with earmuffs, during the Richmond 400 NASCAR race ), and they're fantastic -- unless I need to understand speech clearly. I've got some flange-style rubber plugs that are easier to wear than foam, but they still muffle speech the same way.

I've been using Etymotics ER20 earplugs for the last year or two, and I think they're the best bet for inexpensive, off-the-shelf earplugs. They live up to their promise of smooth full-spectrum reduction. "S" sounds and consonants are still clear, along with any similar noises.