Ultimately SS is the most desirable for me but because I have so many SS pieces I have ventured into various versions of gold.
I really like some of the black watches but I do not own any because I know that I will scratch the hell out of it.
Not into titanium either, looks dull and believe it or not I am not crazy about the "light weight" associated with it. I have a Citizen Eco Drive that is SS and my buddy bought the same watch in Titanium, it just doesn't have that substantial feel associated with weight and it has a dull gray look to it. Just my .02, thanks!
I do not have a favorite case color. I love all colors but sometimes it depends on the actual watch. I know that there are a lot of people that will not buy watches with any plating but I can't imagine a collection of all silver watches. I will say that one of my favorite combination's is Rose-tone and Black.