Another thing I like to see is when the posting talks about what sort of projects you'll be working on.

The latest example of this was GazeHawk's job posting:

"Eye tracking gives you a ton of data with a lot of dimensions. We want to show that data to our users in a way that's easy to parse. That means interactivity: HTML5, Canvas, JS."

Just a single sentence, but it engaged me, got me thinking, and gave me a good idea of the sort of projects they're working on.