I still use pencil and paper, but am pushing the entire office to think on the computer, myself included by the end of the year.
It is not necessarily a reduce tool that affects creativity, even if we aren't quite there yet. An example - Kelly's long flowing lines are, more than he realizes, as a professor once pointed out to me, a function of his "wrist radius." Is that a design criteria? Small wrist, small curves, large wrist, large curves? Similarly, thinking in contour lines is more restrictive than we ever thought. We tend to make things more the same height, as we have a preconcieved notion of what the contour lines should look like!
With current 3-D grading progams, we can concentrate on saying, "I want a ridge crossing the fairway at this angle, starting at 13 feet high, and tapering to nothing by the other edge of the fairway" or whatever. We click in a few points. Then, in a minute, we can see a rendering of our idea! If we don't like it, or need to change it, we click a few more times and start the process again. If we like it, we ship it to the shaper after printing views from three or more angles, and he has absolutely no excuse for a wrong interpretation!
To me, that has potential to be a lot better for design than pen and pencil. To each his own, however.