Since updating to 2.1 I have been experiencing random reboots - recently 3 in the space of a few hours. I think I have traced the culprit. The reboots seem to have stopped since uninstalling Newsrob. A quick Google on random reboots Newsrob reveals reports of similar problems on HTC sense phones which the author believes to be due to bug in sense. Just reporting it here to prevent others tearing their hair out as I was and blaming 2.1 for being buggy.