Since I heard about the Volt initially back in 2006, it was the most logical and practical approach to powering a vehicle that I'd ever heard. Eliminate gas usage on 95% of your driving, but have gas available for long range and fast refueling against the entire infrastructure of the US.
Pure EV's are nothing more than "around town" cars in a lot of the country, which I'm sure is great if you can afford it or fun for early adopters but otherwise just an impractical luxury.
That first 40 miles approach turned the MPG formula on it's head by making clear that miles-per-day is the real metric that people need to worry about.
Going forward, the approach of the Volt could easily be modified to replace the gas generator and tank with fuel cells, bio-diesel, ethanol or any other power source that comes along.
The perk of the approach is that you have 2 options and you aren't purely SOL after a long power outage from a hurricane or other unexpected event. That happens with an EV and you don't have another way to charge it via wind/solar you're left with a very expensive brick.