I very rarely use Caps Lock, yet I'm reaching for Escape hundreds of times per day. Alas, this is the lot of a vim user. By remapping Caps Lock to Escape, I can switch modes in vim without leaving the home keys.
Here's how. In Linux, add these lines to ~/.Xmodmap (create ~/.Xmodmap if it doesn't exist):
remove Lock = Caps_Lock
keysym Caps_Lock = Escape
and then run xmodmap to use the new config:
On Windows XP, create a file remap.reg with this content:
Save the file, and double click it to import the key into your registry. Alternatively, you could Import from RegEdit. This may require a reboot to take.
On Mac OS 10.4 and above, http://c2.com/cgi/wiki?RemapCapsLock says:
Apple now allows arbitrary remapping of all the modifier keys in the Keyboard section of the Keyboard & Mouse preference panel. Simply go there and click the Modifier Keys button to change the mapping (Apple specifically mentions this feature is for developers who use Control often, score another one for us programmers!)
Looking for something different? A change is as good as a holiday, try: MapCapsLockToCtrl - That Caps Lock has to go. Get more Control on your Home row. Here the royal we instructs you to swap your CapsLock and Ctrl keys.