(edit: also see my update for 2012 1st quarter)
In the wake of Gnome 3, Gnome-Shell, and Ubuntu’s Unity interface those of us who can’t do 3d acceleration are left with a decision of what to do about our Linux Desktop.
The line-up of major contenders runs something like this: Xfce, KDE, LXDE, Openbox, Fluxbox, or Gnome 2 (until it becomes deprecated) .
There are several minor contenders out there as well including, but not limited to Enlightenment, IceWM, and the billion and a half tiling window managers out there.
In terms of distributions that support them KDE still has a few major supporters including OpenSUSE, Slackware, Mageia, Mandriva, Kubuntu, and Chakra. XFCE has a growing following in distributions such as Linux Mint, Xubuntu and Crunchbang. LXDE has picked up a few followers between Lubuntu and Pepperment OS as well. Openbox and Fluxbox seem to be rivals in the lower-end machine category and have a few distros among them as well including Linux Mint for Fluxbox and Crunchbang for Openbox.
Now I want to give you an overview of what I see as the strong points and weak points of each:
KDE 4.7 is a great improvement over 4.6. The activities idea seems to have finally come to fruition allowing users to alternate between traditional desktop interface and various netbook or touch-screen friendly interfaces at the touch of a button. In this way, KDE has become the most versatile of the non-Gnome3 desktops. The main problem is that it’s quite resource intensive compared to the other contenders. If you have the machine to run it however, this shouldn’t be a problem. It is also the only QT-based desktop, which can make those used to the GTK (the interface toolkit used by Gnome) feel out of place at first.
Xfce is a formally lightweight-focused desktop environment that has almost become as feature rich as Gnome 2 was and is certainly the most similar. For those who fear a difficult transition away from Gnome 2, the easiest I think would be to use Xfce. Xfce, like KDE provides its own, fairly mature compositor giving you the option of having an effects-rich desktop experience.
LXDE is the most traditional of the modern vein of lightweight desktop environments. It uses a well selected assortment of existing and original applications to cover the basic desktop interface. It’s much more feature sparse than Xfce but typically provides what most users are looking for while being extremely agile.
Fluxbox is a “right-click application menu” style desktop similar to Blackbox. It makes heavy use of editable configuration files and provides a rudimentary taskbar. It is very nimble and requires minimal configuration to get running.
Openbox is another “right-click application menu” style desktop. Unlike Fluxbox it doesn’t come with much of anything, and requires a bit more configuration. Some of the distributions that provide Openbox have already done this configuration for you, like Crunchbang, and provide an extremely fast and very usable desktop experience.
All of the major contenders listed here appear to have a broad following that will help to support development in the years to come. So there’s not much to fear regarding these disappearing off the map anytime soon. As always the Linux world provides realms of choice unknown to Windows and Mac users, and navigating through those choices can be difficult. My personal recommendations go as follows: Xfce for those changing from Gnome 2 that don’t want to adjust much, LXDE for those that need a very lightweight desktop and don’t like customizing, and Openbox for those that need a very lightweight desktop and do like customizing.
My personal setups include Openbox (with tint2 panel) and Xfce, I have however, used all of the desktops listed above for at least a week each.