When I was using my camera all day, I set the the shortcut button to turn off the display, seems like that helped out battery life a lot, without having to keep turning the camera on and off each time I wanted to take a shot. "I need to figure out how I accidentally got into burst mode"...
I've had the S1 IS for about a week now and so far I am extrememly happy with it's outdoor performance... I took it to Sea World over the weekend and ended up with very nice clear pictures, even at full zoom. It captured Shamu mid jump perfectly. Auto focus is pretty slow, so it helps...