Use what you know, it is the least likely to get in the way. I use vim if for no other reason than it saves me from cleaning up the errant ":wq" and the like which end up scattered throughout anything I do in any other editor. If you use any sort of markup realize you will have to get rid of that if you decide to submit it anywhere, most journals and the like will specify how they want it formatted and starting with a plaintext or rtf file saves a step for you, I suffer with libreoffice when I submit somewhere since they generally want word or pdf and it handles the conversion easily enough. Most of the places I submit too specify fonts and sizes as well so going through the work of doing pretty layout serves no purpose for me.