Last year, I had a ridiculous experience in Luton airport outside London, where a security guy told me that my laptop creates a "fire hazard," and couldn't stay plugged in. I asked for a direct quote I could publish and attribute to him, and he balked, saying he wasn't authorized to speak for the airport. I pointed out that there was a Dixon's electronics shop in the terminal full of things that were plugged into the mains and mentioned that I'd bought my power-adapter from a Dixon's just like it in Heathrow the week before. Then I pointed out that the business-lounge (which overlooked the main terminal) was full of people visibly plugged into the same electrical system. Finally he relented -- and the airport didn't burst into flame. Talk about a business-traveler-hostile airport, though.
DFW is a hub for people flying cross-country, but it's not the only one. Free electricity and a laptop-friendly atmosphere are a good reason to choose to fly through Chicago's O'Hare instead of Dallas -- though Dallas does have a killer BBQ restaurant that beats the food court in Chicago hands-down.
Update: Aaron sez, "Technology Evangelist just posted a couple days ago that Minneapolis/Saint Paul International started charging $3 for 30 minutes of juice."
Update 2: Andrew sez, "The Port Authority of NY and NJ provides power poles at Kennedy airport for free.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.