One thing to keep in mind is the difference between “Marchitecture” and “Tarchitecture” (borrowing terms from a book whose name escapes me at the moment).
A geeky numbering scheme for versions is quite valuable for various software components suc as your individual binaries. This is part of the technical architecture.
But I agree with Jeff, when you release the software as a product, now marketing comes into play and “Windows 6.0.6” Doesn’t cut it. Call it something Memorable.
If you’re running Tech Support and need the actual version, ask the customer to use the Help | About box and read the underlying version numbers to get accuracy.