I would say wood. (unless you have the means to do your own fabrication, not everyone does)
If you use a cured wood, and apply a lacquer to it, you wont have to worry about moisture or shavings.
You can mount it on top of a slab of wood and call it good, or you can install standoffs and insert it into a desk with a glass top. It depends on how creative you are, and how much work you want to put in.