2 tips on ctrl
Opening new tab in Firefox
If you're using Firefox (and you should!!), you can open any link in a new tab just by holding down the 'Ctrl' button when clicking on a link.
This also works for the Google bar buttons - enter your search and hold down 'Ctrl' when pressing one of the toolbar's search buttons.
Zoom in/out with the mouse wheel
You can zoom in/out in almost every Windows application by holding down the control button and scrolling the mouse wheel up and down.
Saves me lots of time!