I have two tables in front of each other, and a shelf on the back table. On that shelf I have some books, but mainly, my instruments. This way, I have a full width table in front of the instruments. I like that arrangement very much, I've had the same for years. An additional plus on current setup is that I have access to the back of the tables, so it is easy to attach cables to the back of the shelf, access the back panel of stuff etc.
As the desktop material, it doesn't really matter, the important thing is that the desk is sturdy. You really, really want to have an antistatic mat on the table anyway, so it is irrelevant what is under it.