Do not power off your tablet at night to charge it. It is more wasteful of energy. If you "power off" your tablet, then plug it into the wall, the tablet screen lights up again and says "Charging"... The screen, at least on my N800, never turns off!

If you want to charge-and-go, and have a fully charged tablet in the morning, go into "offline" mode, lock your screen and keys, then plug in your charger. The screen will go black, there will be no network activity, and you will have a fully-charged tablet in the morning. It will stay fully-charged, even after unplugging, for many hours in this state. Then, when you want to use the tablet, just hit the unlock key(s), and your screen comes alive, and your tablet is ready to go!

If you are a hacker, and you start a custom set of services that might impact the "idle mode" power consumption, you should make a script that shuts down these services when you want to go into "deep idle".

These tablets have astonishing power-saving capabilities. I ran my tablet as a GPS tracker in the wilderness for three days, with only two sets of 4 AA batteries to charge it at night. I wasted the first set of AA batteries trying to charge my tablet when it was "off". The screen's backlight, on for 8 hours solid while the tablet was supposedly "off", drained the batteries quite effectively. The second set was much more useful, because I charged while the tablet was "on", and the screen was off.