Depends on what you're hunting. If I'm hunting birds, I ALWAYS wear electronic muffs (Peltors). If big game, a set of earplugs around your neck so you can pop them in before the shot (most times).
Hunting pheasants in corn with electronic muffs is cool. It amplifies normal hearing, so you can actually hear them running away or towards you. Stereo sound lets you know where they are coming from.
My hearing is already a bit hosed from too much shooting as a lad, so I need to protect it at all costs now!