Well, sorry for posting so many times to this thread; I've learned
some stuff and thought about a lot.
I ended up running "apt-get -t unstable install mozilla-firefox".
That upgraded a lot of stuff, including a bunch of Gnome libs, and
also packages like gnome-panel-data to their 2.10 versions, which
worried me since I'm still running 2.8. However, it all worked, and
now I even have nicer Gnome menus ("Apps, Places, Desktop" instead of
"Apps, Desktop", and KDE and Debian menus integrated into the Gnome
menus).
It seems like, since I started using Testing in February, I've
continued to get closer to Unstable by installing more versions of
packages from Unstable. But I've never had anything become unusable
or crash, so I guess all's well. So many light-years ahead of the
Windows experience. :)
