What makes a beautiful photograph?

I was at Barnes and Noble today looking through some photography books and I thought to myself- What makes a photograph beautiful? Is it the subject? The lighting? Colors? I guess the answer to this question might vary depending on who you ask. Here's my answer:
In my opinion, what makes a photograph beautiful is capturing that one moment you don't want to be forgotten, ever. It could be the birth of a child or capturing a simple expression of emotion. That's what is so great about photography. It really is ALL beautiful! This is why I love to take photographs.

What makes a photo beautiful to you?