I've had that happen once before. If I need the phone to sit overnight, I just put it in airplane mode. Otherwise, it's on the charger. However, since Froyo, I haven't had the battery drain issues that others have had. One thing that's helped was to NOT kill apps. Froyo has a provision in it to prevent app killing. If you must FC an app, go to manage applications. Otherwise, the system will just re-start the app, which may include a re-sync. I would also check what kind of signal you are getting. If you're not able to get 3G, the 1x signal will drastically drain your battery. In those cases, again, I switch to airplane mode. Otherwise, I don't have any weird drainage issues with the battery.