My webserver is still on Fedora 12. That would require a lot of upgrades.
Personally, I tend to let my servers stay old and stable. My main server is still on Red Hat 9 but with my own roll-your-own upgrades built from source (but then packaged into RPM form) for services such as apache, sendmail and bind to stay current. And X in any form (XFree or Xorg) has never been on any of my servers. In fact, the only editor I have them is "ed". In the event someone cracks into the system, they'll be so puzzled by its "interface" (to use the term loosely), maybe they'll just give up and go away. :-)
On my desktop systems, I stay quite current. That's why the transition from FC16 to FC17 was painless. It's evolved over the years from Fedora Core 1, upgrading incrementally when each release went gold.
I guess you could say that with servers, I'm a staunch Conservative but I'm a radical liberal (in the non-political sense of that word, of course) with my client-side units. :-)