Just wanted to throw in my 2c: I found this thread after my battery died, and the device would not turn on after more than 2 hours of charging. I thought maybe it was bricked because I (may or may not have

) rooted it yesterday.
It just turned itself on a couple of minutes ago, reporting 5% battery and charging.
Looks to me like the poster above that said that the Droid considers itself dead with < 5% battery is correct -- I think that because I'm using the USB port on my laptop and not the wall charger that it's trickle charging, and hence took >2 hrs. just to get up to 5%.
So my advice is to give your Droid a good loonnng charge before taking it back to the VZW store if you're in the same position as I.