The main thing is to just make sure the surface is nice and flat. Other than that, it really doesn't matter what it is. I'd also throw some ceiling tiles or drywall on top of it since they will take pins better.

I actually built a few planes in an apartment using a building board on our glass dining table. I cleaned everything up and threw it on top of the entertainment center each night. I had to make sure I kept the glue scraped off the table though. Great Planes makes some good boards: http://www3.towerhobbies.com/cgi-bin...?&I=LXPF36&P=0

As for the Somethin Extra, it is a great kit. It builds easy and flys nice.