Eh, I don't really get passing up shows based on art style. I don't think there's ever been a show where I saw the art style and hated it enough to pass it over. For example, Kaiji looks ugly as hell, but I love it! There's a fantastic, intense gambling anime beneath all those terrifying noses. If you can look past a show's appearance, you'll be able to find a lot of great stuff beneath.
In any case, for you I'd recommend Flowers of Evil. If you like Lain, I'm sure you can appreciate slower paced anime. If you want something dark, then this ought to work. It's not a horror, but it builds up dread like no other. It should be on Crunchyroll.