The downloads page indicates that this image includes LXDE, but I'm having trouble enabling it.
3 Answers
When you've logged in, just type startx on the terminal, then it should fire right up.
To have the GUI run automatically when you boot your Pi, you'll need to install something like GDM (sudo apt-get install gdm - this is next on my list, probably this evening). Then to get to a text-only terminal, press <Ctrl>-<Alt>-<F1> through <F6>; and <Alt>-<F7> to return to X.
Gnome
You will need to install aptitude and tasksel before install gnome
Aptitude is an Ncurses based FrontEnd to Apt, the debian package manager.
Tasksel is a tool that installs multiple related packages as a co-ordinated “task” onto your system.
# apt-get install aptitude tasksel
Install gnome on debian
# tasksel install gnome-desktop --new-install
LXDE
minimum set of elements
# apt-get install lxde-core
complete set of elements
# apt-get install lxde
complete Debian LXDE desktop environment
# apt-get install task-lxde-desktop
You can choose more GUI from http://namhuy.net/1085/install-gui-on-debian-7-wheezy.html
goscript. They just run it when their computer boots up or logs in, and it starts all the GUI and other services.