Ask HN: What makes a good job description?

Doing some research for my next project. What I am looking for are opinions from both sides of the desk. Please feel free to add things not listed, to rank things, and to just comment freely.

If you are looking for a job, what do you find to be the most important part of a job description?

If you are a hiring manager, what do you find to be the key elements of what you are trying to communicate to a prospective employee? And what do you find to be the most effective way of triggering a good response?

Some things that seem to go in most postings Specific skills needed Location Salary Company personality Environment Benefits Posted by recruiter or actual company Etc...

Thanks!