Ad photos of road bikes & Mtb's are always shot in that manner (and sometimes over-exagerated) because it is aesthetically pleasing to took at and makes their products 'look' fast.
If your frame and stem allow you to do, a good starting point would be to set the handlebar almost dead level or slightly lower than your saddle and just experiment to see what's comfortable for YOU. Of course, with the traditional quill type stem, raising or lowering is so much easier to do...

George!