All the productivity .... bullshit !!!! However fast I produce code, how much I do it doesn't matter, still my boss would expect more! The only true measure of how much productivity I need at work is how much I must do to avoid being fired ;) Since doing more than others in the team doesn't means to be better paid than the rest of the team I can afford myself to be less productive as usual because I invest in my health and comfort by learning a new keyboard.
Think of it. Is it really that you have to be so "productive" or is it just your boss who discovered that you can be more squeezed like an orange to produce more juice!
Anyway my way to be happy at work is to type as slowly as possible! The slower I am the more interesting and challenging task I am given because I can cope with solving difficult problems, learning new things, researching. Those who type fast stick with typing, bug fixing and so on ... dull tasks. This is not only my preference to the type of spending day but also those "typists" are treated as a labour however high their education is because they only do typing so can be easily replaced with a cheaper ones. IMHO fast typing spoils the carrier path, so invest in your health and comfort but think of what you're trying to achieve in the office!