Having recently gotten a N800, what is the correct way to shut it off. Leaving it in sleep mode or turning it off.? How much difference will there be in battery loss between the different ways?

There are differences depending on what apps you have installed and what you leave running if you put the IT into sleep mode. The default email app and Modest for example, will drain your IT pretty quickly if you have it set to notify you via the LED. Likewise, if you put the IT into sleep and it constantly attempts to connect to a wifi signal, but it can't, the battery will drain.

But, since the IT is built by a phone company, using similar technology, the best way to "put it away" is to put it in sleep mode (i.e., just like with a phone, it's possible to never turn it off). Sometimes, it's a good idea to switch it to Offline mode to avoid the wifi search dilemma.

But, you can turn it off too. There's no harm in that.

-T.

So, not to sound too dense here but what are we calling the sleep mode? The offline mode, lock the screen and keys mode?

When putting it in my pocket, I usually select offline mode, then lock screen and keys.

Yes. But, I would consider "sleep" mode the locked screen/keys and not necessarily Offline. But, switching to Offline is the safer bet.

-T.

The wifi powersaving on the N8x0s is absolutely incredible. As long as you don't have something open that's constantly pinging the net, the power usage in connected versus offline-mode while sleeping will be remarkably similar.

On mine, its not. I only leave mail or a static browser page up. Online runs me down fast enough it'll die over night. Offline will last me a couple days. But the n800 travels in my pocket to work and crosses several networks during the day. YMMV maybe its just mine?

on My new N810 - with the default apps (abnd Claws mail instead of regular email program), I could leve it on and connected to Wifi and the battery drain was minimal - so much so that I only had to charge every other day.

Now that I have a stock ticker applet whcih refreshes every few minutes in getting data, and have modest - which autochecks, the battery drain is more and is noticeable throughout a single day.

So it depends on what you have installed which connects to the networks even in sleep more that the battery drain will matter.

Leaving a browser page up in online state will drain when the page autorefreshes - like a google reader page, or yahoo news page. So that is subjective again.
If there is no significant online traffic in idle mode also, then there is little to no significant battery drain leaving wifi on - I believe.

So far very happy with the battery state on my N810. I only go offline at home and sometimes shutdown at night before I go to sleep.

Like others in this thread, I usually put it in offline mode, then lock screen and keys. I really wish there was an option that did BOTH of these at once, like a true standby mode. Is this possible?

Yes, it's called "soft power-off", but it's broken in the current release. Hopefully after the next firmware update.