I suggest we get off the "lets not move forward notion" and move forward before the US is left behind in the dust, the the younger population overtakes the older population in the industry!
Occasionally, I like to remind myself that software does not do any real thinking. (At least not at the OS level)
The goal is not to use really new software. It is to use what you have to produce work that makes money for the company. It is always about the value equation. New software is just another investment analysis/decision exercise along the path.
You still need education, experience, and savvy to use and apply the output. That is what your client or employer is really paying for.
If you can do that with XP or even an old DOS version, then why upgrade to Vista?