After several nights of experiments. I can confirm that there is something with the 650 that results in apps not totally "shutting down" even if you think you have exited them properly. Any game is a possible culpret as is ptunes and other apps that access the web. If you are experiancing bigger than expected overnight drain, try a soft reset before going to bed. That has helped a great deal in, apparently, 'clearing out' whatever is still draining down the battery.

Also watch out for alarm programs like "Treo Alarm." I love the app, but it apparantly is using resources all night long when I have an alarm set, even if it never gets to the time that the alarm goes off.