I just picked up some ultimate ears super.fi 3 studio ear canal headphones and I love them. They're $99, and they work about as well as ear plugs on reducing noise. The backround noise is cut down dramatically with them on, and I find myself listening at much much lower levesl than I used to... which is a very good thing for your ears. For noise reduction realistically they work about as well as the Bose ones do even though they're passive, on top of that they cost 1/3 as much and don't sound like ass. They're certainly worth considering.
Gary
Gary