Mine's not been charged for 17.5hrs and it's only dropped one bar.
Ok not had much use today, bluetooth connection for the 45 min commute to work, a couple of texts and emails and that's it.
What I'm doing now is actaully turning off the wifi when I'm not using the phone.
Before with the wifi left on overnight it would take around 4-5 bars off the charge. Now with it off it doesn't use any charge at all.
Mine is constantly on 3G too.