I had my 8120 usbed to my laptop last night. When I went to bed I put my laptop into hibernate and went to bed. In the morning my BB wouldn't start up, black screen. I had to pull the battery and everything is working fine now.
One time, probably a few months ago, I plugged my berry into the charger and let it charge. It took an abnormally long time to charge (maybe 2-3 times normal), but eventually it finished charging and I disconnected it right before I went to bed. The next morning it was turned off, and the radio was turned off, and the battery was dead. I'm not sure what happened, but once I charged it up again everything was fine.