Using Caps Lock as a Control key
One the most useless keys on a keyboard is the caps lock key. I have never had any use for this key. For me it is a complete waste of real estate. Some keyboards, in particular compact keyboards like the The Happy Hacking Keyboard Lite, have gotten rid of this key. It is still available by pressing the Function + Shift key (should I would want to go on a rampage shouting in a forum), but the key above the shift key is the control key.
I have now gotten so used to the Control key being in the place of the Caps Lock key, I have tried to reconfigure the Caps Lock key on standard keyboards to be mapped to the Control key. Luckily this is straightforward in most operating system.
On the Mac you can disable the caps lock key in the keyboard using the Keyboard Control Panel and change the modifier keys. Here you can set the caps key to have no action or in fact the action you would like to map to. How To Geek has a nice explanation with screen shots if you need details. You then can go on to map the key to the control key instead or leave it as a dead key instead.
On Linux you have several possibilities. The simplest in to issue the command
xmodmap -e "keycode 66 ="
at the startup of your GUI session. It has the advantage that it is independent of the flavour of Linux you are using. Depending on your flavour of GUI you are using there may be settings in your control panels to have the same effect, but this can change if you change your desktop manager.
Finally, on Windows 7 things are not as easy, as they requires you to change the registry, that is you will need some admin rights to do so. Again How To Geek as a writeup on how to do this.