I use StumpWM:
http://www.nongnu.org/stumpwm/I personally think the whole "Linux Desktop" issue is a bit of a red herring. GNU/Linux (and, I assume, other libre Unixes) is the only widely-available OS I know of where it is even possible to use a graphical environment without the "desktop" metaphor, which I see as a huge step forward.
To me, the "desktop" is all about entrenching the various kinds of boring, repetitive work that computers are supposed to relieve. This insidious metaphor is implicit in everything about how desktop environments are used and developed: the way users are encouraged to scatter icons across their screen for fast access to files, instead of encouraging organization and fast access via searching; the presumed importance of "office" software that most users could replace with a typewriter and a calculator; the focus on making the environment "intuitive" from the first moment one uses it, at the expense of training the user to eventually learn to use their computer more effectively and efficiently.
I would much prefer to see the free software community put its efforts into building graphical environments that eschew the desktop metaphor, and instead focus on making it easy for the user to off-load work to the machine. Part of that task is making it easy for the user to discover what the components of the environment are, how they work, and how to recombine them in novel ways.
A good test for this, I think, is how well a graphical environment supports a task like data entry, because it's the kind of thing that just about every computer is going to have to do at some point, and it is often a mind-numbing task. It's often mind-numbing not because the task is boring, but because most "desktop" environments provide no way to offload the cognitive advances you can make while doing it. After a few records, you know you have to check that field C looks a certain way relative to fields A and B, or that it's faster to enter field E before fields D and B, etc.; but the software you're using provides no way to encode this information, so you have to remember this boring algorithm and execute it repeatedly yourself, instead of letting the computer handle the algorithm while you focus on edge cases.
The challenge is to build an environment that a user can offload the algorithmic aspects of their work onto, without requiring the user to be a full-on programmer, at least not at first.
Free software has already taken some significant steps in this direction. Tiling window managers, the OLPC's Sugar interface, and even to some extent programs like Emacs are examples. We're ahead of the game when it comes to building a new metaphor for working with a computer. We just need to recognize it.