Software

LaTeX word count: TeXcount.
See LaTeX in your Gmail and GChat: GmailTeX (real-time, browser plug-in required).
Instant Markdown and LaTeXing in browser: Socrates (hyperlink-shareable, no plugin required).
Produce LaTeX images online: Roger's Online Equation Editor.
Find the LaTeX name of a symbol by drawing it: Detexify.
Exports citations directly to BibTex from Google Scholar: Google Scholar Settings.
Converting bare text citations to Bibtex: Reference Tagger.
Converting bare text citations to DOIs: CrossRef's Simple Text Query.
My LaTeX header file (bra-ket notation, etc.): riedelheader.tex.
Elegant templates: LaTeX Templates.
LaTeX equation image creation: LaTeXiT.
LaTeX editor: TeXstudio with MikTeX.

Mathematica Autosave!
Fast partial trace of multi-qubit density matrix: [Mathematica Notebook] [Plain ASCII].
Fast, formula-based computation of Gaussian integrals: [Mathematica Notebook] [Plain ASCII].