Recommendations for iPhone Bluetooth Headsets for Listening to Music? I have a Motorola ROKR S9-HD headset and the Previous and Next buttons don't work with my iPhone 4.

I'm thinking about buying a different headset to replace it.  What options exist and which are the best?  Does the previous and next function work on any of them, or is this an iPhone problem?
I'm pretty happy with the Nokia BH-214 for my iPhone 3G. It's relatively cheap, and it turns any headset into a bluetooth headset.