I followed a Tesla roadster for about 30 miles on the M25 a couple of years back...looked like a seriously quick and nimble car and it was entertaining watching all the repmobile 3series BMW drivers having a go at outrunning it and failing
Model S with the high capacity battery really can do 300miles on a charge, if you are not being careful it'll do about 250-260 and can outrun pretty much anything this side of top end Sports cars : one just did a drag race with a new Corvette Stingray in the US, the result was a 1:1 draw and you can't carry 7 people in a Corvette!
I see a few Nissan Leafs around here, range is sub 100miles but they seem to be ok on motorways and can keep up with the rest of the traffic.
'S future innit? At the moment the real work is using electric vehicles as performance cars as opposed to runabouts , all the upcoming ferraris, BMWs, Porsches and McLarens are hybrids with the electric systems used as performance boosters running alongside a a normal engine but also with full EV modes for city or heavy traffic use too.
Normal electric cars for the rest of us with decent range at a reasonable price will be about 5-10years down the line.