I use Shure E2C. You can get them cheap on eBay for about $60.00. I like IEMs because of the isolation and they take up absolutely no bag space. Shure, Etys, Westone, and Super Fi make the best, IMO. Which one you pick will be based on your budget, your taste, and most important, how much you actually use them in the field. I use E2Cs because I don't use them in the field that often, but its nice to know they're there.