I think this is a wrong question in this context. Software developer don't recommend OS to people, he delivers software, and the more platforms he supports, the better.
Moreover, if someone has an old box with 98 or NT, what could he do when he don't want to buy a new PC?
However the Python guys are probably doing the right thing here because the right approach to making windows based business systems reliable is to disable everything possible on them, isolate them as much as you can, get things working and NOT upgrade them unless you absolutely have to.
Windows XP SP2 is basically the minimum version of Windows that you can use and expect a reasonable user experience. That includes the ability to install new (recently released) software. If you insist on old operating systems, then you should expect to run old applicatoins on them.
-- Ken Thompson
For web developers this is fine, since they don't need to install programs. However for those of us that need to install programs, it's going to be sticking with python2.5 (or even 2.3 if you want better compatibility).