Is there any battery app that tells you to the exact percent of what your battery is at?
You can try "Battery Left Widget", read the description though, it takes a while for it to calibrate to your phone's battery so within a few days it should be dead on, especially if you let it die completely and install it once you have a 100% charge.
I use the app and love it and it is pretty accurate for me, but just know that it's always only guessing, albeit a pretty good guess, based on your usage.
The Droid only reports battery percentages in 10% increments. I think there are programs that, using historical data, calculates down to 1-2%. But anything less than 10% increments is not real data.