Burning Man Daily Bag
This is the bag that sticks with me through out the entire Burning Man event. It has pretty much everything you need when away from camp. It's so easy to get distracted out on the playa, that you really need to bring this stuff with you. Heck knows when you'll get back to your camp (hours, sometimes days).
C'mon, I'm a boyscout at heart. What do you expect?
EDIT - Updated version of the every day carried Burning Man bag found at: www.flickr.com/photos/xmasons/4866493873/