It is amazing how much I rely on Vim on a daily basis and yet how small a proportion of it I actually know.
Same. I use d$ (i.e. d and the movement command $) to delete to the end of the line. Apparently you can just use D. Also, I didn't even know you could do N | to move the the Nth column (e.g. 30| moves to the 30th column).
S is likewise super nice: it clears the line and puts you in insert mode.