http://www.markpeterdavis.com/getventure/2009/07/management-equity-compensation-benchmarks.html

Management Equity Compensation Benchmarks

I'm
often asked by entrepreneurs for equity compensation benchmarks.  They
want to know how much equity they should give a COO, a VP or a CEO. 
Understanding these numbers is important for sizing an option pool and important for creating compensation plans for new members of the team.

Wilson Sonsini Goodrich & Rosati,
a venture law firm, recently published the results of a study on the
typical equity compensation packages for key managers after a Series A
investment.  These numbers provide pretty useful guidance not only for
compensation at the time of the Series A, but also for compensation at
the Seed or Series B round as these metrics can be adjusted for likely
dilution to back into a benchmark for equity at the Seed stage or
otherwise.

It is worth noting that these numbers are not the
end-all be-all for equity compensation.  They might fluctuate as market
dynamics change and may not be representative of the entire market. 
That said, they should provide entrepreneurs with some directional
guidance.