Mike--
I just checked my 650--and the first page after coming out of standby does appear to be a bit lighter. Not a lot though. In fact I don't think I would have noticed this at all if I wasn't consciously looking for it.
Now--regarding the battery life--that is not normal at all! I've only had my reader for three weeks, but the battery life does last. I've been using it fairly extensively and it hasn't yet gone under three bars. I have charged it once or twice via AC and have connected it to my computer to transfer stuff to it a few times. I'm definitely getting a lot more than three days of stand by and light reading!
Hope a hard reset does the trick for you. Otherwise I think your plan of returning it is a good one. I would think that you shouldn't have to worry about the 30 days though--if the battery is only lasting three days, you have a faulty unit and the return/replacement should be covered under the warranty.
dordale