As far as battery life:
1. If you are using it throughout the workday, and battery life is running out, then I would keep it plugged in to a power socket so it doesn't drain batteries at all.
2. If you are travelling with it, then it is likely that at some point you will be near an outlet or laptop to recharge... if not, then bloody read a book for an hour or two

After 8 hours of continuous playback, don't you get cauliflower ear?? After a 2 hour plane ride, I am ready for those earbuds to be OUT.
I can envision situations where once in a great while, there are situations where one isn't near a power socket or laptop. But these are rare, odd, and infrequent circumstances... and the benefits of a high resolution color screen (which nearly everyone would prefer) outweighs these unique and infrequent situations, in my opinion.