DC Vertigo markets comics that are for a more adult audience. I really enjoyed Y Man and Books of Magic. I know the mini series introducing Books of Magic is available in ebook form and all of Y Man. I'll second the Fables recommendation. I am starting to build up my X Men franchise books, but I have read those since I was a kid and am enjoying getting caught up.
I wish the ABC books were available, I would rebuy most of those titles.