As per the suggestion below, I added a PTC.
I'm unclear how to get HaD to not crop these images. I'll post all of these files, including the images up on GitHub today or something, that should get around it.
I like adding features like these, because it turns it into a better piece of engineering This whole project is intended to be fast, easy, and cheap, so the best part about features like that - and all of the features on this board, really - is that they're totally optional.
For example, I'm probably not even going to populate most of the components on the very first board I build. I'll solder in the 40-pin DIP socket, the decoupling caps, USB connector, and the pulldown resistor. Literally nothing else is mandatory, assuming I'm okay with sticking to 5V logic. The fuse, inductive choke, and switch will need solder bridges.
That's also why I haven't included an external oscillator. There is very little reason to use one, now, unless you need very high speeds or good stability. I rarely need either.