tough question...
I chose language. langauge is pretty close to story, but I actually don't really care about the story, as long as I can understand it.
Of course, artwork is paramount. Colour and censorship are just visual factors added onto the artwork. What I've found, though, is that it's really rare for me to bother keeping a manga or a doujin unless it's in English. Then, the artwork merely has to be good. For me to keep hentai that's untranslated, though, the artwork has to be amazing.
But then again, that's for keeping and rereading. I'll take a glance through whatever (like, censored, uncoloured, untranslated, etc.) if the art's pretty good.