I listen to KCRW in the car and Pandora radio which I stream through the stereo from my iPhone. I've been listening to everything from Caribou to Conway Twitty. If I'm going on a longer car ride I'll download some podcasts.
If you're lucky enough to be involved in a film that's about something very real and that you hope will continue to hold up in 20 years' time it just gives you more energy and makes it feel all the more worthwhile.