The universal bane of anyone who regularly uses headphones, tangled cords can make the simple task of plugging in a frustrating hassle. Cue in the CordCruncher Headphone's elastic sleeve design, adjustable anywhere from 16" to 3.5', and effective in preventing cords from winding themselves into knots tighter than shoelaces...
Available in Matte Black, Pearl Blue, Rocket Red, and iGizmo White, the Kickstarter project is on the horizon of becoming a real retail product in the coming weeks; the MSRP will be $24.99.
And if the CordCrunch sounds a bit rich for your blood, there's always the dental floss DIY solution (just remember not to use used floss).

Shaw's Original Fir...
$24.99 for a cord keeper? I don't think so. But this post did inspire me to create my own cord detangler by placing my cord between a few thoughtfully placed strips of velcro. Heading to the sewing supplies basket right now...
With as many folks that hate the tangle issue, why haven't any headphones/earbuds makers addressed it? I'd pay extra for a set that didn't tangle.
I have a set of ear buds from UrbanEars that is cloth-covered from the jack to the split, and I have NO more issues with tangles. Also, heat shrink tubing is pretty easy to apply to headphone cords... That stuff is like $3.50 a bag at a hardware store.
Nice idea with the shrink tubing. I'd not thought of that. I even have some sitting around.
I've been using an old plastic container from those travel/purse/small size q-tip packages to hold my ear plugs. I wrap them around my hand and put them in the plastic box (maybe 2 x 3 x 1 inch). I never have a cord tangle problem and it saves the buds from getting gross or damaged from getting pulled on.