what are your favorite skill for your class that you don't use because you cant spare the slot, but would love to have in your build. (try to keep it less than three), and why you don't use them (if it is any other reason than just because you can't spare the slot)

for me my monk would LOVE to use cyclone strike and crippling wave,

cyclone strike because its freaking awesome and would work wonderfully with sweeping wind by pulling them into its aoe.
extra reasons: none, just the cant fit it in

and crippling wave, because with cyclone strike it would allow me a lot better crowd control
extra reasons: slower attack speed, and much lower proc rate than Fists of thunder/ thunderclap