I don’t believe that personal revenue has anything to do with the value of the website. $200 is a fair average CPA amount to value a site by, given that the site is sending a minimum of 50 RMP per month.
This is what I feel to be a fair formula:
(((Past 3 months total RMP / 3) * (1 + monthly growth+ or decay- percentage)) $200) * (12)
Obvious other factors to include are PR, age of site, incoming links, advertising expenses, and quality of traffic.
Hope that helps,
Dan