I recently purchased the Apple In-Ear Headphones, which I really like. I still have a first-ten iPhone (until June?) and they work well. The volume control isn't in play, but that was to be expected.
The sound quality is a definite upgrade. I was worried about the complete isolation I've experienced with some other headphones (great on a plane - flat-out dangerous walking the streets of Chicago), but they provide good isolation while allowing some degree of awareness of street noise. The wearability is an improvement, as well.
One odd thing... Whenever I'm wearing them on a CTA bus, I experience intermittant static shocks in my ear. At first, I thought it was a fluke but it's been consistent for a month or so now. Is anyone else experiencing this, or is it just me?