If your domain name has a dash in it, it is still worth something as long as it has good keywords in it. Search engines like domain-name.com much better than domainname.com since it can read domain-name.com as two seperate keywords, and therefore index it better than just domainname.com. If you are developing a website (which will recieve most of its traffic from search engines), and not for just pure domain speculation, then a domain with a dash in it would be better than without. Otherwise, I wouldnt suggest to register or buy domains with dashes in it since people dont really like them.