At the moment I am using a Oak dining table, and I have to say it's one of the best Desks I have ever used, it's just the right height for me (6ft 6in) and I can have a 15in laptop and my 27in iMac on the desk and still have room for my Humidor and a few reference books.
I am planning on getting a new desk at some point, but I need space more than anything at the moment and it's low on my list of priorities.