I am up between 4 and 4:30am each day. Usually get to bed around 10pm, and average maybe 6 hours sleep, which is perfect for me.
I've been this way for maybe 5 years now, ever since going back to school and studying for some things. With kids and all, it is the only "free time" I have. I've gotten so used to it, I can't imagine the way I used to be. (Sleeping until maybe 5 minutes before I actually had to get up and get to work, LOL).
I get up this early no matter what, even when on vacation. I kind of enjoy the alone time, early morning coffee, and the quietness. Rest of my family is up anywhere from 7am to 9am, depending on the day.