Charcoal can be fun, but it is super messy. Make sure you cover anything nearby and/or don't touch anything you don't want to get the charcoal on. It gets on you, and there is dust that comes off that gets over everything else.
I did like using it though. Interesting medium.
As for other choices, there's pencil, pen, marker, ink, paint, pastels...
Ink is another really interesting one. You could even use tea if you want your greyscale image to have a brown tint to it.