I've found that off-the-shelf earphones won't stay in my ears when I put on my helmet. So, I've been using Fuze custom earphones. They come in a package with a set of earphones and two containers of a type of "putty" material. You put the bare earphones in your ear, then work the putty into your ear, around and over the earphones. After 15 minutes, you have a set of custom earphones, perfect fit for your ears.....all for less than $40.
I just ordered my second set and when I ran into a problem, the folks at Fuze were very responsive and took care of everything. Hats-off..... or maybe that should be "Helmets-off" to a company that not only makes a great product, but also takes care of their customers quickly and professionally!