@caveman, again, and other interested parties..
Powertop:
The battery reports a discharge rate of 169 mW
The estimated remaining time is 22 hours, 18 minutes
Display off, kbleds off, wlan on. My not-that-good battery at 90%.

Anyway, display hogs quite a lot power, soo, I quickly put up replacement /etc/acpi/handler.sh for acpid to toggle display and kb leds on/off with lock switch. Note that though it puts display on/off, it does not disable input. There are ways to handle that from X. I'll see if I can figure something else too, will be reporting back.

EDIT: Well, I added few arguments to the script so you can lock the input too, you will need xinput and something to execute a script on XF86ScreenSaver keypress, like xbindkeys, which I use.