I've been using only 3G lately and data always on. I have to test this with WiFi also if there is impact to battery.

This is very interesting. I had to close my data connection (3G) to save my battery about week ago. But last friday I forgot my data connection on and after many hours I saw that battery seems to be almost full. I was surprised because I didnt have to recharge my phone about 8pm that day. Next time I did charge was next day 3pm.

My normal usage is like this: I browse web about 20-30 minutes, use gps about 30 minutes, internet radio 30-60 minutes (bluetooth headset), play crimson fields 30 minutes (today), mfe gets mail every 15. min and gmail every 30. min. And ofcourse calls about 30-40 min today.

edit: + foreca and facebook widget always on.