So, a couple of months ago, during our monthly visit to Costco, my eye was caught by set of battery-powered under-cabinet LED lights.
I thought that these might be a useful addition to the safe, so I tossed them in the cart.
After I got home, I decided to eschew the screws that came with the lights, and just stuck some velcro to them, and some strips of velcro inside the safe.
Now, whenever I open my safe, the lights fire up, and I can see the interior. I have no idea how long these things will last, but assuming they've got a decent life span, I'll be pretty happy with them.
Amazon sells the same set, but they're about $10 more.
http://www.amazon.com/Megabrite-Wire..._sim_sbs_hpc_1
The motion sensor on the lights doesn't always pick up the opening of the safe, but a quick wave of my hand and they come on.