I also look at the art style first, and only find out about the story after I've played it. As for voice acting, personally I think it's best when it's there, but it's okay if there isn't any , as long as the story and character writing can flesh out the overall content. Otherwise, if I only judge by the art style and the story turns out to be really boring, I'll end up dropping it halfway through.
But there's also another category of games where I don't really like the art style, yet the story is exceptionally good. I usually end up playing those because someone recommended them and sparked my curiosity. Some games really do have great stories that are overshadowed by their art style and character designs.