I like to listen to audiobooks while hiking in the Santa Monica mountains. The ear buds that came with my iPhone are awful -- they fall out of my ears every 30 seconds or so when I walk. These comfortable headphones from Coosh have soft rubber rings that fit around my ears so the buds don't fall out. They also come with a mic and on-off button so you can make phone calls with them. I'm very happy with them.
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects