If you're happy with the current version of OSx why should you upgrade to the new version? Why is one company (MS) held to a higher standard? I think we ALL know why, and the numbers tell the tale...
If I'm happy with whatever software I'm running, the vendors are going to have to come up with some new software that I must have to make me switch.
Vista may have some new functions, but I don't percieve an immediate need for them.
I'll update when I buy a new computer.