Funny you should say that when I just finally got around to upgrading
a client's production servers from potato[*] to woody last week...
One of them was even the main xdm server, which users connected to
from their X stations, so it's not just a case of "well, nobody looks
at it, so they don't care"; everyone was quite happy continuing to
use 3-year-old versions of their applications. I have not heard
about a single complaint regarding dated apps or old-looking
interfaces or anything of the sort. (There are a few users who
habitiually gripe about "it's not Windows", but newer versions of
non-Microsoft software wouldn't affect that anyhow.)