A while ago I switched to the Dvorak keyboard layout. I haven't mentioned it much since then here, but the switch has stuck.
I've started another keyboard experiment as of yesterday. The Caps Lock key is effectively useless, and in a prime keyboard position. Some people like putting Control on that key, but I think that's because many keyboards actually had a Control key there, thus making it a habit, not a logical choice.
The thing I like about Dvorak is that your hands don't go flying all over the keyboard. I thought about the key that actually sends my hands flying most often, and being a child of the computer era (not the typewriter era), that key is... backspace. I probably use backspace as much as or more than some letters (cough), but it's up there on the corner, basically requiring my entire left hand to leave its position. (I can theoretically reach up there without my left hand moving but in practice it does.) No amount of analyzing text can turn that up as a commonly used key. As a Dvorak user, I've obviously already jettisoned "habit" as a criteria for my keyboard layout.
So, I've mapped Backspace to Caps Lock. I did that once before but I didn't switch because I habitually used the old key; this time I completely unmapped the old backspace key, so at the moment hitting it does nothing at all. I've actually made the transition now.
It was much faster to learn than Dvorak, and so far I like it. I don't know if I'll stick with it long term, but we'll see. The other thing is that you can try this without switching to Dvorak, it's completely independent of that.
Biggest problem so far: Accidentally hitting "Tab" instead. Tab is used to change the focused widget in UIs, and accidentally hitting Tab, followed by other keys, is a real pain. Biggest pain: Tab'ing out of a textbox in a browser, then hitting Backspace, which is a keyboard shortcut for the back button. I'm considering remapping tab onto the old backspace key (Tab is more useful to me than average thanks to emacs but the way I use it is still as a control key, not a typing key), and then that opens up the Tab key for something useful. However, I'm holding off to see if the accuracy problem doesn't solve itself with practice to see if I need to make that change.
Biggest benefit: You don't lose your left hand home positioning so you can probably recover more quickly from mistakes.
As I write this I realize that there may be an even better setup than using Caps Lock for backspace as there is something I use even more than Backspace, which is Shift. If this change is stable, I may remap Tab to Backspace, Caps Lock to a Shift, and the current Shift to Control. Heh, dropping even one key from the standard mapping really opens up possibilities. Why not optimize something I spend so much time using?