It's getting to that point in the price/performance curve where battery-powered LED lighting fixtures are disposable and practical. A prime example is Sylvania Dot-it LEDs, stick-up lights that cost less than $10 and shine for over a hundred hours.
Stick the power-sipping pocket-sized lights almost anywhere, and press the middle whenever you need a bit of illumination from the three white LEDs within. You can take them elsewhere and stick them up again, thanks to their 3M sticky stuff that works kinda like a Post-it Note. Available now.
Product Page [Sylvania, via treehugger]