So a while ago, I learned about the way that Seinfeld manages to stay consistent (something I have quite a bit of trouble with).  You can see the full details here:

http://lifehacker.com/281626/jerry-seinfelds-productivity-secret

Building upon this, I decided to create my own "chain" which I'm posting below.  It's my minimum daily routine that ensures that I'm eating regular meals, exercising, working and accomplishing non-urgent tasks.  I specifically focus on a routine that has breaks and optimizes for how much energy I have.  This ensures that the routine is sustainable. 

Writing down the routine helps to allow you to tweak it everyday depending on how you think it can be improved (as routines should be tailored to your personality).  You can look at it as agile development, but for your life.  Each day is a cycle at the end of which, you evaluate and tweak every night.  Also a routine encourages your body to develop a habit over time.  Soon, these activities will be as easy as brushing your teeth.

My chain

Morning routine
- Get up and eat breakfast + read news
- Brush teeth
- Change
- Go out and walk outside for 20 minutes
- Come back and work for 2 hours straight (don't check e-mail until noon)

Flexible minimum
- Three meals a day
- 2 hr of work a day (at least :-)
- 30 min of exercise
- Take care of one (non-urgent, non-rote) task (e.g. set up a doctor's appointment, buy new shoes, etc.)