This new battery lasts exponentially better than the stock.  The battery that came with the phone was a 1300mAh battery.  These new 1900mAh work great after some slight modification.

For fitment in HTC G2 you need to trim the hooks off the pin side of the battery.  Because the fitment in theses phone is so tight it is also needed to remove the red sticker to allow the battery door to snap shut properly.