Let's start with Canon's answer.
But how many shots on a set of batteries? Read http://www.dpreview.com/reviews/canona710is/11
According to http://www.usa.canon.com/cusa/support/consumer/digital_cameras/powershot_a_series/powershot_a710_is#Specifications I see a range of 2,000 to 16,000 shots for a 2GB card.
As to the speed, I see no indication this model will take advantage of the higher speed.