There's been a good bit of discussion about this. The consensus seems to be that domain names mean a lot less in the SE algo than they used to -- hyphenated or not. In case you didn't catch it, here's a related thread [webmasterworld.com].
In my experience, if the keyword isn't hyphenated for easy parsing by the SE, it's not likely to give you much of a ranking boost. Even with the hyphen, the domain name is not high on the list of factors in the algo at most SEs.
However, having the keyword in the domain name still helps the site a lot, mostly by encouraging people to actually click on the link. Most people will check out a domain that contains their keyword before they'll click on one that doesn't. The domain is perceived as more authoritative -- and people don't need hypens to recognize the kw.
This search in AV might be worth analysing from this perspective. The #1 site has 29 first page rankings in major search engines for this keyword. search [altavista.com].
I am not at all sure they made it on title alone, even though that clearly weighs in heavier than anything else. Observe #8, where kwd is in the third position. That would seem to leave #28 to be explained. My guess his that the kwd density is too high.
Thanks Tedster. Hi Rencke. re position 28 I think you are right about kwd at 4.08 it's over two points higher than I am used to seeing on AV these days - do you think the lack of anything like a heading is a factor too?