If you’re a web developer, Emmet is an easy to learn macro language that speeds up typing of HTML and CSS. Its supported in lots editors (via plugins). I’ve personally used in Komodo Edit (back when Emmet was call Zen Coding), Geany, and (my current editor of choice) vim. Once you invest the timing learning it, it saves you a lot of time and is very hard to live without.
Here’s a good intro to get you up to speed: Faster Workflow: Mastering Emmet, Part 1 – SitePoint.
New to me was that some online coding tools like jsfiddle now support Emmet as well, sweet!