Since Nokia's latest "update" of the N800 firmware, softpoweroff no longer automatically locks keys and screens. This "improvement" has made the softpoweroff setting next to useless. I do get the distinct impression that softpoweroff (which I used before Nokia s-c-r-e-w-e-d it up) tended to consume less battery juice than the "lock screen and keys" option, which I'm forced to use now (and which I think is identical to letting the device go into standby on itself). Still, it could very well be that my blind hatred towards the Nokia software "engineers" has clouded my powers of guesstimation.