Which keyboard layout makes the most sense from an ergonomical standpoint?

I agree with the premise of John Lambie's answer but would take it even further. The ultimate solution is not a keyboard at all but direct thought input. However, that seems far fetched and user dependent.  Also, who in their right mind would trust a corporate built device that can read your thoughts?  Believe it or not, there is a solution that is closer than you think. There was an accessibility research project to develop an in-ear device that could detect what the wearer was speaking by monitoring the changes in air pressure in the ear as they spoke. Using this mechanism it is not necessary to actually vocalize. All you have to do is make the shape of the words in your mouth with your tongue.   Apparently, it works and was intended to help people who had lost their voices (and potentially for the military). This technology could actually be used for private non-invasive text and speech communication.  You wouldn't  need to type at all; simply move your tongue as if you were speaking to yourself.   Users wouldn't even need a screen or anything in their hands at all.  Connected to a cell phone it would be tantamount to voluntary global telepathy - people communicating and searching information databases with no external evidence of doing so.  The technology exists but sadly, the research project lost funding. But to answer the question more directly,Colemak (http://colemak.com) has been computationally proven to be more efficient and ergonomic than both Dvorak and Qwerty.  And it's easier to learn.