Hello Everyone

Am registering a bunch of domain names just for seo purposes, as the titls says, i need your views about the use of dashes in a url, is it better for seo or not. Am not worried about the user side because as i said, they are only for seo purposes.
I think that it doesn't matter anymore. Google parses both foo-bar.tld and foobar.tld the same way (AFAIK). I say, try not to get my-cool-keyword and stick with non-generic names like Yahoo, Bing, Flickr, Facebook, etc.
Thanks samer. After trying out some keywords with and without a dash on most major search engines, it seems that it doesn't matter as you said, but am sure one of them is preferred over the other. I think i will try getting the non-hyphen one's, and try the dashes if one isn't available.

If anyone else has anything to add based on experience (ex. tried but fuc**d up), pleaaaase, share it here before i do. :)
Well...I "tend" to think that long domain names with hyphens are more used by spam sites...but this doesn't mean that SE will treat ur site based on that unless ur content is really that bad; check this article:
http://www.guruofsearch.com/domain-name-with-or-without-hyphens

Please note that, search engines always try to think like the "users" to improve the user experience obviously, so don't ignore this point.
Thanks Xhack for ur input, i registered a bunch today, and tried to avoid hyphens as possible. After reading some posts found on other sites, i think it doesn't matter that much to search engines.
10 days later
I also think that hyphens doesn't matter to search engines, but to avoid it is a good option. I also believe in not taking unnecessary risks. As you had purchased then I hope it will surely work out.