What you will need really depends on the domain name itself...a good domain name and Alexa ranking alone are generally not enough to reliably monetize, but it is a head start that many webmasters do not have.
I have sold quite a few domain names for $10k+, and to me, the $$$ can (and would) talk me out of the thought of developing an entirely new site for all but the best domain names.
If you are already in the adult game and can just change up one of your existing site templates and increase your overall traffic in general, I could see the value. If not, it will take you a long time to make $10k off of a brand new site.
Having said that, the quickest way to monetize will be with affiliates and advertising since you already have some decent foot traffic. This is really a short term solution though, if you want to get in it for the long haul you will need to decide what approach you want to take (blog, tube, etc.) and buy some content.
If it were me, I would try to sell the domains and hope you get another $10k offer...
