I just received my MW600, Sony Ericsson's new blue tooth headset. Seeing as it supports the X10 family of Android phones I am hoping that it will work 100% with my Nexus One. Sure, there is already FM radio support in the Nexus hardware, but there aren't any drivers for it (not that I am a huge radio fan anyway).
First of, the Android support at the moments isn't 100%, i guess this will be changing as soon as the X10 hits the stores, but for now you don't see the name of the contact calling nor the name of the track you are listening to in the display. Apart from that it works really well.