I made a call last night whilst music was playing. The call rang and rang and I eventually hung up. The music didn't start back up again..

I also noticed that the headphones weren't beeping when I hit the play/pause button.. I also found I couldn't turn them on and the blue light stopped flashing.. hmm

when I got home, a brief google revealed this thread and someone else mentioning reseting the head phones..

I tried the three button reset, nothing happened.. no lights or noises..

I put them on charge.. I tried resetting again.. nothing.. puzzled and a bit more googling later I tried "turning them on".. they turned on and I was able to start the music playing again (I'd paused it when I realised nothing was working)

Thing is, this has happened only once and I do use them a fair bit.. It actually seemed more like the battery was flat (and yet I charge them daily and use them for at most 3 hours)

I didn't need to re-pair and I didn't need to restart the phone.. I pressed the play pause button and the music started again..

I have found that the headphones perform terribly when wifi is active.. out on the street using 3g they're better than they were with the N97 I was using previously!