What editors/IDEs are available for easing the process of writing TeX/LaTeX documents?
Please state some useful features like code completion, spell checking, building final DVI or PDF files, etc.
This question is undergoing a systematic refurbishment, see Let’s polish the Editors/IDEs question on meta. If you’d like to see another editor feature covered here or to take care of an editor that’s not covered yet, share your ideas in that meta question.
List of editors
Links to answers.
Archimedes
Atom with language-latex and latex packages
Bakoma TeX Word
Emacs with AUCTeX
Emacs with WhizzyTeX
gedit with the gedit-LaTeX-plugin
Geany with GeanyLaTeX
gummi
Inlage
JOVE
Kile
KTikZ
Latexian
Latexila
LEd
LyX
Notepad++
Overleaf
Open LaTeX Studio
Papeeria
QuatraTeX
RTextDoc
DMelt
Scientific Word
Scientific Workplace
Scribes
Scribo
Sublime Text with LaTeXTools or LaTeXing Plugin
ShareLaTeX
TechWriter
TeXlipse
Texmaker
TeXnicCenter
TeXnicle
TexPad
Texpen
TeXshop
TeXStudio
TextMate
TeXworks
Verbosus
Vim with LaTeX-Box
Vim with LaTeX-plugin
Vim with Snipmate plugin and rubber
Vim with vimtex
WinEdt
WinShell