How to video capture your computer?

I want to make some videos of what I'm doing on my computer. Software walkthroughs, showing off tricks you can do to make your computer better, etc. Nothing that you don't already see on youtube already.

What software lets you record what you're doing on the desktop? I know there are a lot of good editors out there, but I can't remember one that lets you tape what you're actually doing on the computer where you're editing.

Suggestions, please?

 

I should have phrased it differently.

"Which software does the BBS Team prefer when doing their video captures? "