robho - 12:03 am on Nov 3, 2010 (gmt 0)
Will you have to sign a no-compete agreement for a particular time? In other words, are you selling just the domain names, or the domain names with a business?
Big difference in what action needs to be taken. For example, if it's just the domain names you could ask for a deferred completion for a few weeks or more to give you time to relaunch under a new name, forward traffic, and try to move backlinks (but get some money up front in case they change their minds!).
The buyer may not like this, they may be buying the names partly for backlinks, in which case your price will need to be higher as you're starting from scratch.
I have sold a major site with content, in that case I had a no-compete for a couple of years. After that, I relaunched under a new name and eventually beat the old site, but it took years. I've since ignored all offers, can't get a decent return on cash compared to the regular income from a site.