You must also factor in the dimensions of the table in relation to the chairs. Having a table too high for the chair or bashing your knees every time you sit makes a table crap. Also, one must consider table tops; my work desk, for example, has a glass on wooden top which is rather uncomfortable on the wrists when typing.
Now that I think about it, I might have stumbled on this years most important question: is a desk a table (like a bureau)?