I'm perfectly happy with the 36" width especially since it will be up against the wall and my only access to the tank without getting in it will be from the front and the sides.
I can tell you from experience... Even on a 36" front to back tank, it's a looong way if you have to place something on the bottom! I needed to put supports across the top of the tank, to support myself, to be able to place live rock and corals near the back... BUT...it's worth it!