I got a new iPhone recently, and I had been trying to find a good headset that could double as headphones, handle switching between calls and music, had good sound, was easy to put in my pocket, etc.
I had bought one version, returned it dissatisfied, and was trying another one before I left the Apple Store. The sound was horrible, and I complained to a "Concierge". He said "well, why don't you just use the microphone on your headset that came with the phone?" Huh? What button?
Well, if you look closely at the picture, you'll see it on the right. A tiny little microphone. And if you squeeze it between your fingers, it will answer/hang up the phone or pause your music.
I just tried it out and it works perfectly. I am duly impressed.