Ok, I'am creating a bunch of domains however I don't know if the words should be seperated by dashes I do know however that they should contain the keyword for example should I register the domain like LouisVuittonHanbags.com, or like Louis-Vuitton-Handbags.com
For SEO purposes, it doesn't matter imo. Domains without hypens are considered better (more valuable) than those with.
But you also have to think about it from the POV of the repeat visitor: If you have a long domain name with no hyphens, it can be tricky to remember what words it was composed of when you come to type it in later as it just appears as this long blob of a name.
Sure, hyphens might help the visitor remeber the site's words, but I've personally found that it's a big hassle to, when typing in the actual url, to type in a site with the hyphens as well.
There's some great tips starting here: http://forums.digitalpoint.com/showthread.php?p=333582#post333582
I've read just the opposite in seo books. I've been told hyphens do matter because the domain name is seen as separate keywords. I may not be true, but that is what I've heard. I sometimes used hyphens but sometimes I don't. Honestly it probably doesn't matter.
With word stemming capabilities, the domain name with or without hyphens will make little difference IMO, at least in Google. For an example of why I think this, check out a Google Search for webmaster forum and then look at the url/file structure of the results - you'll see the word(s) you searched for in bold; both show up with and without the hypen and singular and plural.