What are the Best Earbuds for Running?

The earbuds that came with my iPod died yesterday. The plastic covering over the copper wire had broken several months ago, and I’ve always had issues with the earbuds falling out of my ears from the jolting of running, but it wasn’t enough for me to take the trouble of looking around for new ones. But yesterday the left earbud quit working entirely, and I wasn’t down for just one earphone, so now I’m trying to figure out which earbuds will stay in my ear while I’m running and not fall out unless I yank them out myself. Any suggestions?