Definitely my dad.
He's always been big into movies, so I liked to watch movies with him on the weekends when I was little. My favorites were always the science fiction movies that he grew up with, like "War of the Worlds," "Invasion of the Body Snatchers," "Invaders From Mars," "The Thing From Another World," etc. This expanded into a love for most things SciFi.
Still not entirely sold on fantasy, though. Anything D&D, Tolkien, or D&D/Tolkien-inspired tends to bore me. I guess that means I'm really only half-nerd.