If the CEO only needs $40k/year to live comfortably that should be his salary.
If the CEO left a job making $200k/year, or has a family/mortgage/other responsibility, he might need more.
I think paying whatever-the-CEO needs to live comfortably with a maximum cap of around $100k seems pretty reasonable.
1. http://techcrunch.com/2008/09/08/peter-thiel-best-predictor-...