PSA: You should remap your capslock key
While remapping CapsLock to left Ctrl is a great idea, it's also worth considering remapping left Alt to Ctrl (if you use Emacs) - that way, rather than sticking your pinky out to type while holding down Ctrl, you can hold Alt with your thumb. Probably less awkward. (Both beath bending your pinky down to the normal Ctrl, though.)
Also, changing CapsLock to Esc is a great idea if you use vi.
I remapped it to control and then got some use out of the caps lock light: http://dustin.github.com/2009/02/09/caps-lock.html
I map mine to Alt/Option on the Mac. It fucking rocks!
Caps lock is useless. The only downside is that whenever I use someone else computer I find myself toggling Caps.
I tried this, but it was too much hassle to learn :/
As a touch typist, it has always seemed to me that making it easier to hit Ctrl with one hand than the other is going to build bad habits.
Unfortunately MacOS doesn't let you remap it to Shift, which is what I usually mean to hit instead.
Or, you know, learn to type accurately.