Music, art, science (esp. evolutionary biology), animals, and revelry.
People with similar interests, any Homo Neanderthalensis
Lately - Explosions in the Sky, The Red Sparrows, Isis, Mono, Mogwai, Boris, Sigur Ros, Sunn 0))). Otherwise - Ministry, older NIN, Sepultura, Skinny Puppy, Fear Factory, White Zombie, Neurosis, Lightning Bolt, Jucifer, Tool, A Perfect Circle; and other stuff like The Cure, Siouxsie and the Banshees, Ascension of the Watchers, New Model Army, The Sisters of Mercy, Big Black, Joy Division, Swans, Pj Harvey, Nick Cave & the Bad Seeds, Bjork, Portishead, Kronos Quartet; plus Jane's Addiction, Faith No More, Nirvana, Soundgarden, The Doors, Led Zeppelin, Black Sabbath, U2, Morphine, and lots of other stuff along these lines.
Requiem for a Dream, American History X, Fight Club, David Lynch, Tim Burton, The Gift
The educational, the extreme, and the funny: 24, Lost, Discovery channel, National Geographic channel, History channel and so on...
Fight Club (Palahniuk), Women (Bukowski), Story of the Eye (Georges Bataille), She (Haggard), Dracula (Stoker), Frankenstein (Shelley), Slaughterhouse-Five (Vonnegut), Planet of the Apes (Boulle), Sphere (Crichton), The Blind Watchmaker (Dawkins)
MoM, Charles Darwin, Leonardo da Vinci, Ludwig van Beethoven