It's not just gasoline, don't forget about all the things made from oil... Plastics being the big one; short of a giant leap in technology, I don't ever see us moving away from plastic.
Something's got to generate electricity for those electric cars, something has to create the hydrogen to run the way-in-the-future cars. We can probably do alot of it with solar, wind, nuclear, and coal, (we probably have enough coal to last us until humanity blows itself up and becomes oil for the cockroach people), but it'll take a long time to wean ourselves off of oil 100%.
And Vaseline! What will we do without Vaseline!