Looked at /etc/rc.d/rc.4 and...
Gnome Desktop is scheduled to run first and if it's not there then KDE gets loaded.
I started using linux in Fedora with Gnome and I loved it. I'd like to try Gnome in backtrack. So how would I go about installing the Gnome(gdm) for backtrack? Would I have to use slapt-get | gslapt? I've had bad experience with that package manager. What would be the best way to install Gnome for backtrack?
I'm not speaking from personal experience here, but you probably want to look into something called GWARE, it's Gnome packaged for Slackware. I believe all you need to do is download the build script and it should do the rest for you once run.