Spend the extra money on traffic, content, etc... A domain, with few exceptions, is only as good as the site.
Look at some of the big sites, thehun, dannisharddrive, al4a, and many others, they break all the "good" domain rules...So, for me a domain name is less important, unless you have a way to aquire sex.com, than building a good quality site. What defines Quality varies depending on what kind of site it is as well
