Updated Jan, 21st 2013
I realize this is not a tiny habit, or even a small habit, but it's really important.
For me, waking up early is the start of a positive chain reaction. I can get the majority of my work done by lunch on weekdays. On weekends, I can put in a good couple hours of work on my projects, contemplate the big picture of my life, etc. while the kids are still sleeping.