Seth Godin said something interesting about domain names.
Don't focus to much if the domain is free. Instead focus that the doesn't have a lot of google results. Because most peole do not use the adress bar they use google to find a webpage. I don't claim this is totally but Mr Godin got a point there.
Depending on the site, this is something I've found as well. However, this has only worked for sites where I'm not trying to get a lot of repeat visitors (so, it works well for one-off storefronts and things like that).
Regards, Marco