When I lived in NYC, a company called Revel had pushed a bunch of electric scooters onto the streets, and they were fabulous. They are pretty beefy, went 25mph which is fast enough for most NYC streets, and had a very decent range (40miles or so). So they aren't a commuter bike for most Americans, but if you live and work in the same city, they are amazing.

The make and model is a Niu NQi from a Chinese scooter manufacturer. I've never seen them outside of NYC and SF, but I'm sure they are legal everywhere in the US. They are a great 50cc moped replacement IMO.