FitBit Aria - couples with the personal Fitbit that I wear on my belt everyday. It connects to our homenetwork via wifi and *magically* keeps track of your weight without any need to track it yourself. The data just shows up in the Fitbit dashboard every morning. With just 2 days of data in, there clearly is no intelligence gained, but I expect to generate some data over the course of a couple of months. The tricky part is going to come up with a routine to weigh myself in the same manner everyday.
Now all I need is some sort of device that monitors all the chow that I stuff in my piehole. Then I'll be lean and mean.