Regarding the size of the desk? That depends on the size of the monitors and how you wish to locate them, I think that the type and size of desks depends on how much room you have available and how many monitors you wish to place. Best thing to do is measure it yourself.bump..
What Keynes said,
my two screens (24's) are about 1200mm wide, so you will struggle, to get a case and a three screens on a desk, unless it is MASSIVE.