Etymotics - hands down.
Web site here
You are probably looking at the Isolator line here - more the fifty bucks though.
Though you can use the Etymotics noise isolator fittings on other brands of ear buds - take a look for "etymotic hybrid" on Ebay, a random example here - Less than fifty bucks.
(I am going have to figure out how to get images into these responses - sorry)