Continuing my look at keyboard short cuts, another one I find useful is Ctrl+A. This is known as the "Select All" command.
Essentially, you click once on a page and can then Ctrl+A to highlight all of the material in that window. This is useful when you want to copy and paste things or delete a mass chunk of material. I find it faster than highlighting with a mouse.
This command works in most document and spreadsheet programs as well as most browsers.