NY Times featured a study today by a DePauw University professor who found that the less people smiled in high school yearbook pictures, the more likely they were to later divorce. Granted, nobody is arguing for causation, but this is at least an interesting correlation.
http://www.nytimes.com/projects/magazine/ideas/2009/#p-1
Proposed next study: University IDs as a predictor of marital contentment. Proxes, anyone?