I've been using Shure's SE315 for a while now. They work great, come with 3 different sized ear rubbers and foams (I like the foams best for riding), fit well under a helmet and are super heavy duty. The cords are also detachable from the earbud so they can be replaced if needed, although the cords are also heavy duty enough I doubt if that will ever happen.
http://store.shure.com/store/shure/e...oryID.12165500