I'm sure someone will come along with specific numbers, but it wouldn't consume much power because of the relatively weak (but efficient) processor and graphics card it uses.
It would seem that they don't even spin the disk down then, if its at 17 watts. I wonder if it decreases further after some time (like several hours).
Anyway, its too much for something that is doing nothing IMO. Does Wake on Lan work over WiFi, is a 5 second delay while it spins up the disk too long? Perhaps a bunch of "fixes" will come out of the community...its a pretty interesting device to hack.