Doug,
I find it VERY humorous that you'd ask hundreds of Boxster owners on this forum if you should buy a Boxster or a Corvette. It shouldn't be too hard to guess what we'd tell you, would it?
I think you should take Richard's advice (BruceLee) and drive both, decide what you'd enjoy driving for as long as you plan to keep it, and then make your decision.
As a little kid, I dreamed of owning a Porsche. What did you dream of owning one day? Buy that car and find out if it was worth dreaming about all these years.
For me, it was a Porsche, for which there is no subsitute (including the Corvette).