that pretty much says it... when i try to install gnome, i follow the dependency path down to libpoppler1-glib, which it needs...

(in synaptic)
libpoppler1-glib:
Depends: libpoppler1 (=0.5.1-0ubuntu7) but 0.5.3-0ubuntu1 is to be installed

if i try force version, then i get

To be removed
kde
kdegraphics
kdegraphics-kfile-plugins
libpoppler1-qt

Now, as far as I understand it, libpoppler is a pdf-reading program. Why would it want to remove kde and the other files, just to upgrade?

It may be that "kde" is not all of KDE. Debian/Ubuntu have some packages called "metapackages" which are just there for ease of install. Sometimes programs want to remove these wrappers, but they're not really programs. In Debian, kde is actually kde-core. The metapackage "kde" contains other metapackages to install things like koffice, games, typical system management tools, etc. So the package "kde" can be removed and it doesn't uninstall anything...

So I gues I'm saying, I would give it a whirl. You can always reinstall KDE...