Just a note on "end user" sales.. You can't always assume that any end user has a vestige of a clue about the value of domain names. I have had three approaches (for 3 different names) from end users starting / developing businesses (genuine end users, because I checked them out). They all said more or less the same, which was that my domain name was the perfect fit for their project (I checked this too, and they were a totally perfect fit..)
Since they were not domainers as such, I made the initial $$$ offer (I don't usually) at their request. These were modestly priced in the mid to high hundreds, as I wouldn't have minded the sale. The reaction back in all cases was stupified amazement and splutterings that they had a figure of no more than $75 in mind. This for a short word-perfect generic or very brandable domain, that would cost their business less than the cost of a one-time newspaper ad. Oh, well the Dallas Cowboys, "I thought it was $2.75" (re their non-purchase of Cowboys.com) mentality is prevalent across all business markets and levels I suppose.