If you spend a lot of time in the computer and/or sailing on the web, you might have some keyboard shortcuts that you use in a daily basis while working in the computer.
Whether you learned it by mistake or you learned it at school or in post like this, they all make your work in the computer a lot easier and faster which is definately a plus.
Here is a very useful table that lists keyboard shortcuts for Windows XP/Windows Vista, Mac OS, KDE, GNOME.
There are a couple of keyboard shortcuts that I find myself using all the time while working on Windows, they are Start button+E to open Explorer Directory and Alt+tab to sort through the programs I have open. What about you? Do you have a favorite keyboard shortcut that has become necessary in your daily work?