I use QWERTY, but I always remap Caps Lock to Left Control because I use Emacs (both in Windows and Linux).
I was amazed how easy this was to do in OS X. I could only do this with registry hacks on a PC, and I can't remember how I used to do it in Linux.
remove Lock = Caps_Lock
remove Control = Control_L
keysym Control_L = Caps_Lock
keysym Caps_Lock = Control_L
add Lock = Caps_Lock
add Control = Control_LYou can also swap in Esc into that slot, if you're a vi user.