I don't care for porn. It's too chaotic for me, as well as repetitively boring. I like to just go onto a site like Facebook or MySpace and look at cuties still dressed, and just use my imagination. When I'm in bed, which is the other place I jack off, I go into all kinds of erotic fantasies I've come up with over time. And I must admit, I do fantasize about hot chicks I failed to fuck when I froze in their presence, even as they flagrantly came on to me, back in my college days.
Normally my imagination is all I need to turn myself on. However, I do enjoy good erotica (Anais Nin...), and the sexual energy in certain music can work like an aphrodisiac for me.