You had it correct in the first drawing. DC ground is right where you pointed. In the AC world, "ground" is a safety aspect not a current carrying conductor. The 'ground' or third prong of the plug is connected to the chassis as crutschow mentioned. AC has HOT and NEUTRAL, and for the purposes in this circuit, doesn't matter which is which.
In your last drawing, GND is in the wrong place. You had it right in drawing #1 and then changed it to be wrong in drawing #2.