in reply to The most useless key on my keyboard is:
I'm not sure this qualifies as a "key" but lately the key that I'm "pressing" the most is the flat spot on either side of the pointer tablet on my laptop.
Hitting it sharply is a better word for it.
You see, the video on my IBM T30 keeps cutting out on me while I type, so I'm forced to smack it with my fists every once in a while so I can see what I'm typing.
I get a sad, sick, tactile satisfaction out of smacking the blasted thing......