If you don't mind the additional size, go with the seidio 3500 battery.
http://www.mobilecityonline.com/wire...mpaign=froogle
This battery easily lasts me 2 days between charges with my normal usage. Heavy users would easily get more than a day out of this. The only complaints are the volume rocker is harder to adjust, and the back cover will sometimes pop off. But this battery is definitely lasting much longer than the stock one.