I have about 10% of my net worth in bitcoins, and my goal is to keep it about the same.
If it lives up to its potential, you don't need to own huge numbers of bitcoins to be set for life.
While that's true, if you continually sell down your holdings to stay at 10% you'll never end up with a significant holding. Probably better to go with the SSS plan if you don't just plan to hold for the longest time.
https://bitcointalk.org/index.php?topic=345065.0