With gasoline around four bucks a gallon, do consumers want Hummers or more fuel-efficient vehicles? General Motors sees the future and is evaluating whether to even keep the Hummer brand. Meanwhile, CEO Rick Wagoner told GM’s annual shareholders meeting that the company will shut down four truck and SUV plants, while boosting production of hot-selling Chevrolet and Pontiac cars. Looking further to the future, GM’s board has given a green light to the extended-range electric car, the Chevy Volt, which recharges by plugging into an electrical outlet. Prototypes have already been shown and GM says it is on schedule to have the Volt in showrooms by the end of 2010.