I bought an older style table desk that is really really sturdy. Be wary of the new plastic folding tables since they don't handle a machine very well - they make my machine start to jump...
I love love love my old table desks. They have metal legs and a laminate top and are just fabulous. Sturdy as anything. I have two of them set up in a L shape and I sit on one side and my cutting mat is on the other - it's a perfect arrangement since my room is so small.