This is one that I was looking at. http://www.amazon.com/Seidio-Innocell-E ... 134&sr=8-1
A friend of mine just got one for his Samsung Android phone. He turned it on, turned on wi-fi, gps and bluetooth and it was over 2 days and still had a good charge. I was looking at the reviews on the battery for my original Droid and some people said it didn't work after 2 months and I wanted feedback from some geocachers that might have used it extensively with the GPS on.