I enjoy reading about the progress Tesla is making, but I will not consider buying any electric car until the price is < $30k and I can at least drive from the bay area to Tahoe and back for a ski weekend on a single charge.
You'd need a pretty big tank to do that using a gas-operated vehicle; it's around 400 miles. My Accord V6 gets 250-300 miles on a tank, the Model S gets around 265.
One key difference is how low you'd be willing to let your remaining range drop. You probably wouldn't feel much fear driving around with 40 estimated miles left in the Accord. But I imagine 40 miles left in a Tesla might cause a little anxiety. The same-numbered range of a gasoline-powered vehicle is lengthened by the high confidence of being able to refuel within a few miles.