The Guardian Dual Function Light
The Guardian Light (available now; order here; $17) is what Tom found after a three-month search for a safety light that would meet his requirements: rugged, easy to use, works as a safety light or an interior bag light, and worth your hard-earned money. We think you'll be very happy with it. Read more about the Guardian Light on the blog or visit the Guardian Light page for more pictures and information.
On a personal note: the Guardian Light really does help you see what is inside of your bag. I've used it countless times to find my keys. I have an old prototype Utility Tote that I still love to use despite the fact that it has zero o-rings and thus no place to attach Key Straps, so I end up tossing my keys inside of the bag, seldom being able to retrieve them quickly in dark places/at night...until the Guardian Light came along!! (I sort-of rigged the light around the handle of the tote: don't try this at home! Use the o-rings you have!)