For some reason, I didn't come across Tesla Motors until November of last year.
I had followed the development of fuel cell cars for some years (since at least 1998), and done as much reading as I could on Mercedes' and Honda's prototypes. (I went so far as to buy a few shares in Ballard, the fuel cell manufacturer -- a good lesson in the financial consequences of misunderstood physics.)
At some point, I ran across AC Propulsion's T-Zero. Then, in April or May last year, I remember being taken with a Business 2.0 article on the WrightSpeed X1. A month or so later came news of Prof. Schindall's (MIT) adaptation of carbon nanotubes to enhance capacitor storage capabilities, and a couple of weeks later, news of a French researcher enhancing battery capacity with a similar technique. At that point, it became clear to me that fuel cells were out, and batteries (and perhaps eventually capacitors) were in.
I can't remember exactly how I came across Tesla Motors. Whatever the case, I still have the email I sent on the same day -- November 10 -- to my then-girlfriend, with the subject: "So, like, this is my new dream car..."