I'll bite; how useful is the Menu key really? Is there something in your workflow that is benefitted by having it? Totally agree with Home/End/Insert/Delete being required on any keyboard I use.
While on the topic of what keys are on the keyboard and while thinking of Fn keys, I really, really, really wish that keyboards would give a key code for Fn+___ for each and every non-modifier key. It’s absurd that such a simple opportunity for good macro-capability is discarded, and you can only use Fn with the few keys (on laptops, commonly around 16–20) the manufacturer deigned to hook up (e.g. Fn+F1 as XF86AudioMute, Fn+F7 as XF86BrightnessUp, Fn+Space as PrintScreen, Fn+Left as Home, that kind of thing) and the rest are just swallowed in the keyboard firmware. How is it that as far as I can tell no one has done such an obvious and obviously useful thing?
I also use it every now and then to change things up when I feel the RSI sneaking.