I've seen Fullmetal Alchemist. I've watched a fuckton of anime. I prefer weird horror stuff.
If you like weird horror anime watch Another, When They Cry, or Hell Girl. If you like action-horror, try Gantz, Future Diary, Steins;Gate, or Shiki. I'm going to assume any anime fan has seen Death Note, Deadman Wonderland, and Serial Experiments Lain.