I have a road and mountain bike and will tell you for commuting the road bike will be better unless you're really pounding on it constantly.
Due to spine and hand problems and a wrist surgery I unfortunately have had to give up the drop bars. I would recommend a cyclocross to you as well but IF you like the upright riding position better there are hybrid options. I just picked up a Trek 7.5 FX to accomodate my spine/hands and in the first week my top speed has been 26 mph. Not great, but I am more than comfortable for commuting.