Speaking of Octavia Butler, I read Kindred and I absolutely must recommend it!
Fair warning , it heavily deals with the topic of race, not in a way that I find preachy, but some may not be too comfortable with all the punches she doesn't pull.
Butler's work is a dark and occasionally very tough read, I find. She has this way with narration that doesn't gild anything, but states it so frankly that you are compelled to take it as fact and just immerse yourself in the work.
You know, I haven't read "Kindred" even though it's probably her best known work. I should go get it from the library. I read the Parable books and "Fledgling" and liked those. I thought "Fledgling" was a wonderfully original take on vampires. You're right about her books being dark. Some of "Parable of the Talents" was hard to take. Butler is great though, no doubt about that. :)