I was leaning towards the Plantronics Voyager Pro HD.
It features A2DP.
However, it is NOT bluetooth 4.0.
Does that matter? I read that BT 4 is not compatible with BT 3 or 2, although if the device supports both, then it's fine.
I want to use the same headset for my Galaxy S3 as well as my Nano 7th generation. I really like the over-the-ear form factor of my old Plantronics Voyager, and I like how the rubber part that goes in your ear doesn't detach when I put the headset in my pocket. Any other suggestions?