I'm going to be doing a bit of traveling soon, and hoe to use my powerbook as much as possible in airports/airplanes. while I've become quite adept at finding outlets in airports, that doesn't hold true for planes. So in the hope of watching a movie in-flight, I was thinking about ripping it to my hard drive, in the hopes of extending battery life. Am I right in assuming that the powerbook will use less power if playing a movie from the hard drive, as opposed to spinning an actual DVD? So too, using headphones should help the battery life a bit too, no? (not that I'd use it without headphones on a plane...) Any other suggestions to make the most of battery life en-route much appreciated.