- Maxing out the 401k early

- Marrying the right girl, also not marrying the wrong one

- Ensuring (in my own religious views) my eternal salvation. This one brings great peace of mind.

- Doing volunteer book reviews for programming books. This has opened a great many doors.

- Giving up alcohol after my kids appeared

All these have brought great payoffs. I can't say I made any of these decisions out of wisdom (most were just luck), but I am very happy with the way they've all turned out.