Good comment Hawk. While it is true that the search engine doesn´t necessarily care about the "uppercase" letters when doing searches, we have found that conforming to standards (like Capitalized word comma space Capitalized word) allows the spiders to index the site more efficiently and makes it less likely that the spiders will miss something.
While there is much discussion whether commas are necessary, we have had more success using the comma separated words compared to non especially in terms of keyword phrases. For example see our article on getting search results on the first page.
Moreover using something like, could be taken as spam.