Available as an add-on item on Amazon, this Kuru Toga pencil has a cool feature that rotates the lead incrementally every time you press it down on paper. That way, the tip stays nicely rounded. Here’s a video of the spring-loaded clutch mechanism in action:
The pencil also has a metal sleeve that protects the lead, sliding into the pencil as the lead gets shorter. The sleeve retracts completely so you can lug it in a bag without having to worry about it getting bent or breaking off.