Seems like a good way to get things rolling in a sub like this. I like hearing what people have done with their systems, so I figured why not ask?
My daily driver laptop runs Gentoo with deblobbed gentoo-sources and almost all \@FREE licensed software. I can't drag myself away from chrome-binary-plugins, and my fscking laser printer requires a nonfree driver.
I'm running Awesome window manager with slim for logins and a fairly fat-free monolithic kernel configuration. After a complete X login, I show 270 MB memory in use, which is cool, but I also value that number greatly as I do a lot of software development involving reading and manipulating big files. The more I can cram into memory, the happier I am at work.
URXVT serves me well as a terminal emulator, and I use a combination of Atom and vim for editors.
Anything I'm missing? Let's hear your setups too, if you care to share!