Front door should open in, not to have to shove your guests back away from the door so that you have enough room to open the door to let them in. If you have'nt enough room for the door to open in then do open it out, I have often come accross this, but once you have the room to open it in definately open it in even if its only an inch or two to spare when you open it in.
French Doors (Double Doors) & Fire Escape Doors should always open out.
As previously said, your house, you will be using it for a long time, the salesman will be long gone.