I can measure battery drain with various Nokia N800 WiFi and BT settings but I would be entering into an area with potential unknowns.

Measuring idle current on the AC-4U charger/adapter was a no brainer. Properly measuring what the WiFi radio in the N800 draws would involve some reverse engineering to be sure I was really measuring what we want. I'd hate to come out and say authoritatively the WiFi radio simply consumed 18 milliamps only to learn later that it is much more complicated because of how the clever designers at Nokia implemented it. Ditto for the Bluetooth. Throw into the mix that I believe the 400mhz CPU throttles up and down too, I'd not know how much of the power during a Gizmo call was related to the WiFi and how much was the CPU processing the voice data. Same goes for WiFi web browsing. I can adjust the transmit power on my Linksys WRT54GS with DD-WRT. I don't know what effect that may have on the N800 802.11 radio's power consumption. If my DD-WRT setting is at it's lowest, would the N800 boost it's 802.11 thinking my router was very distant?

Cellular phone radios increase and decrease transmitter power as needed to reach a cellular tower. For example, if you have a 20 minute conversation on a cell phone when you are at the outer ring of a cell tower's range your handset battery will be drained more than if you were right next to the tower. The handset had to use maximum xmit power to stay linked to the remote tower. Nokia may have similar technology in the N800 for the 802.11 WiFi. I just don't know.

I endeavor to be accurate. There is just too many possible things going on for me to feel comfortable in making accurate measurements isolated to the N800 WiFi and BT consumption.