The current KDE release for Debian 7 is 4.8.4. The kde-full meta package will provide all KDE applications as well as the window and display managers. The KDE user environment provides a System Settings application just as GNOME does, but it is a bit more comprehensive as it includes the ability to configure KDM, the display manager responsible for the login screen. In fact, because of this, some administrators use KDM as the display manager, even though the default session may be GNOME.
Other desktops
XFCE and LXDE are the most common alternatives to KDE or GNOME, although there are others. Neither one provides a display manager for login screens, although LXDE recommends LightDM, a lightweight display manager. XFCE and LXDE (as well as LightDM) retain the old desktop metaphor, and are designed to place a minimal load on the system, making them appropriate for older hardware.
During the time Linus Taroalds abandoned GNOME3, he ran XFCE.
Like both GNOME and KDE, both XFCE and LXDE provide a system settings application to control the look and feel. LightDM also provides a graphical settings utility.
Showing your best face
Take time to at least look into the settings for your chosen display manager. Unless you are running a server that never sees a graphical login, this is the first and last thing your users see. You may also want to look into appropriate backgrounds for your users' desktops. They don't need to be fancy but they do make an impression.
