Front doors are personal. Beyond displaying your design taste to the public from the exterior, they can show off as little or as much of your interior too.
Below is a glass store-front door installed in a home. I like the idea of all the light in the entry, but it sure is transparent. There would be no way to hide from the religious groups or salesmen stopping by on a Saturday morning! Frosted or tinted glass might help the situation, though.
image from Home and House Design
image from All the Best Home and Interior Design
I think I like these doors better, especially the one on the right end; it’s a good compromise between a solid traditional door and an all-glass one.