I, myself, have been using the wet measuring cups for all my baking and cooking needs. Since I have been baking more recently, I think purchasing those dry measuring cups would come in handy and provide more accurate measurements! (Ahem, hint hint :)
Did you ever notice that there was a difference between wet and dry measuring cups? Sure the difference is only slight, but when it comes to sensitive baking recipes that smidge or two of flour can really make a difference.
Check it out for a very interesting read!