Since upgrading to 2.0 my bluetooth has started acting up.
While driving, the hands-free system in my car will occasionally (about once a day) show pop-ups on it's screen that the iPhone has disconnected. It usually reconnects within about 10 seconds, but this did not happen before the 2.0 update.
I have also noticed that the AT&T signal meter does not always update during a bluetooth call. For example, driving home I generally know the stronger & weaker areas of signal, but on a recent call both the phone & bluetooth display showed no signal for the duration of a 20 minute call I received after driving through a weak signal area.
It might be happening at other times, but I've only noticed it while it was connected to bluetooth.