Virtual PC, while a very 'cool' piece of software, in my experience turns fast and expensive Macs into slow and even more expensive Windows Machines.
Virtual PC not only has to emulate Windows, it has to emulate the hardware of a PC and then emulate the machine instruction set of the Intel CPU.
The programs you want to run have a repuation for demanding the very top of the line PCs to run on.
I guess it really depends on how much you will be using the above programs and what else you will be doing on the machine that will be running 'native'.
If it's only occasional use to view other people's work and to make minor changes, go for it. If you will be doing heavy CAD work, don't.