Tools that make my life better
The first tool that I love and can't live without.
LANSCHOOL! See http://www.lanschool.com -- I have used a version of Lanschool since the day I started teaching in a modern networked lab. It really really helps keep students on task.
Plus it is much cheaper and easier than dealing with a projector. I just wish we had bigger monitors so we could do more on the screen at once.