People who look at a Tesla as a pure $$$ spent on gas over time question are completely missing the point.
The fact that you save money on gas is basically the least awesome part of the Tesla. I don't have one, but my coworker does, and good lord is everything about this comic 100% accurate:
http://theoatmeal.com/comics/tesla_model_s
It's like when the first iPhone came out and some couldn't understand just how far ahead of the competition it really was because they focused exclusively on battery life or something.
Yeah, when I read that comic a few months ago it made me really want one. Unfortunately I hardly spend money on gas because my work is 1 mile commute and I walk/jog most of the time, so it does feel a little bit like not the best value proposition for my situation.
Still, gonna be real tempted when this comes out.