Just switched to the AmiWM desktop for my Linux installation, I am typing this in a custom build of Emacs. I built this from source and it is good for a first try, I need to get the Xaw3d development packages and some more X development packages to get more features, but it works very well for a first try. I just needed to type sudo apt-get install texinfo to get the makeinfo program to be able to build the documentation, but otherwise it worked really well. If only I could build the latest version of Xawtv then that would be the best thing. I just rebuilt it with the Xaw3d libraries and it is fine now. Just the thing for editing all my files and getting some stuff done. AmiWm looks just like the Window Manager for an old Amiga PC. This is very light and useful for any desktop user who does not want any bloated desktop environments on their machine. Very nice for a retro look on a modern Ubuntu machine.
The best thing about a slim desktop is using the terminal more often and not bothering with bloated text editors. Emacs or VI is all you need. Here are some very useful tips for VI: https://stackoverflow.com/questions/1218390/what-is-your-most-productive-shortcut-with-vim/1220118#1220118. These shortcuts are very useful for any VI or VIM user, and will speed up your workflow greatly. There is more information and screenshots of AmiWM here, this website has a lot of information about the Window Manager and a download link to the source code.
https://www.lysator.liu.se/~marcus/amiwm.html.
There are plenty of desktop environments available for Linux now. But I like looking at old ones from time to time. Here is the GitHub of AmiWM. This might be more recent code. The benefit of using a nice WM like this is the speed of the interface compared to Gnome and KDE. It is able to be personalized and customized with various other programs like Xeyes, Xload and a couple of Xterms open. That is all you need sometimes. Window Maker is another alternative for the Linux desktop. This is modeled after the NextStep desktop interface and has a lot of very useful applets that have varying functionality and usefulness. Here is a very nice listing of Window Maker applets: http://www.cs.mun.ca/~gstarkes/wmaker/dockapps/sys.html.