Wedding chalkboard sign - making it look like chalk vs pen?

I think as long as you use the black chalkboard background, using a paint pen will come out neater looking. It will still look like a chalkboard. I've used chalk markers before and they really do come out looking like chalk. You can rely on them.

Once you finish it, if the writing is too smooth looking (as if done with a pen), take a small piece of sandpaper and lightly sand over the area for a more distressed look.

What if you did the sign in chalk and then sprayed with a matte sealer to set the lettering?

This might help you decide: http://www.organizinghomelife.com/chalk-marker-review/

I recently discovered that you can actually purchase a piece of Chalk board as places like Lowes, or Home Depot. Then you can use Chalk and it will be useable in the future as a chalk board as well. You can also go online and find a removable adhesive chalk board product. It is pretty neat. and it can be used and reused, and write on it with chalk.

I found this on Amazon.com

Chalkboard - Peel and Stick Contact Paper 79 X 18 inch Self Adhesive Blackboard - Removable - Reusable

so those are two options for you.

Michaels sells liquid chalk...I beleive there is a Martha Stewart version.