I noticed my 8820 running down awfully fast the other day. No 3rd party apps open. Pulled the battery for a few minutes, and after the next charge everything was back to normal.

I did install WebMessenger prior to my batter issues and noticed that this app starts up automatically every time the bb boots. Didn't find any settings within webmessenger which allowed this to be turned off (didn't like the app enough to really dig). Uninstalled, then pulled the battery as described above. No probs, 2+ days battery life since.