I am going to go ahead and say its a necessity to have a good front door. It sets the tone for the whole house and is a powerful symbol for the home. As Jeremiah Eck (remember him from The Distinctive Home series?) states "A good entry isn't about show. It should have a graceful quality, be inviting, and be well proportioned to human scale" (The Distinctive Home). Personally, doors are sort of like stairs and fireplaces for me - I just love them. They are equal parts functional and aesthetic which is the perfect combo for my tastes. I am especially fond of dutch doors. It takes the right house to pull one off but when done correctly they are real stunners.