Personally, as much as I like linux, drivers issues are simply a pain, who want's to have to spend hours in forums and on google before buying a monitor to make sure its compat?
But drivers issues asside, linux is great for me as a developer b/c, with apt-get ( or the non Debian/Ubuntu distros equivalent), I can grab libs on the fly in no time plug them in and start testing/building, the source is always there for me to run gdb on, I have an amazing list of cli utils (in coreutils, binutils & co), also having complete control over my os and tab switching through 5 terminals all running my nifty lil' tasks just makes me happy :) Also emacs keyboard shortcuts (which work just about everywhere on linux) allow me to fly on just about any task, who wants to traverse the keyboard and hit 'END' to go to endline?