TeXShop!

Texmaker is a free LaTeX editor, that integrates many tools needed to develop documents with LaTeX, in just one application.

TeXstudio is an integrated environment for writing LaTeX documents. Our goal is to make writing LaTeX as easy and comfortable as possible. Therefore TeXstudio has numerous features like syntax-highlighting, integrated viewer, reference checking and various assistants.

Texpad is a LaTeX editor designed for straightforward navigation of projects of any size. When Texpad opens a document it scans through it, looking for LaTeX structure commands and any included files, then it presents you with an outline view with which you can swiftly navigate the entire project.

BaKoMa TeX system for Scientific Publishing. One of its main features is instant preview: The document is typeset as you write, providing true WYSIWYG experience not usually found in LaTeX editors.

Online site for viewing, annotating and collaborating on PDF and Office documents. Upload a document, send a link to invite feedback. Runs entirely in browser - does not require any plugins. Free version allows uploading a few documents a month - pay-as-you-go options if you need extra storage.

Inlage (Intelligent LaTex Generator) is a shareware LaTeX Integrated development environment that allows the user input LaTeX by using Windows 7's Math Input Panel. The shareware version does not allow saving or compiling after 5 minutes of testing.

JLatexEditor is a cross-platform open source LaTeX editor. The editor is in constant development. It is well-tested on Linux and Mac OS X, but has to be considered pre-alpha version, and only for experimental use for Windows.