The bottom line is knowing the type of home, room, patio or porch you have will enable you to narrow the choices and choose the perfect door system. You‘ll also need to consider the climate where the doors will be installed. This will dictate material selection, how the door is hung and the style suitable for that particular application.
When you are looking at the front door designs keep in mind the rest of your house. If you have a specific style throughout the house you should try to have the front door design match. It would detract from the style that you have already worked so hard to create in your home if you choose a door that clashes with this style.
Most of the time when you seek out a door, you will see many of the same things. Not necessarily that all doors are the same, but rather you will see many of the same styles. While doors even within styles are technically different, they still retain the overall feel of the style. If you want a truly unique door, you may have to think outside of styles and even outside of the box.