Agnostic. Atheist. Non-observant Jewish. Neo-pagan. Very commonly, three or more of these are combined in the same person. Conventional faith-holding Christianity is rare though not unknown.
Even hackers who identify with a religious affiliation tend to be relaxed about it, hostile to organized religion in general and all forms of religious bigotry in particular. Many enjoy ‘parody’ religions such as Discordianism and the Church of the SubGenius.
Also, many hackers are influenced to varying degrees by Zen Buddhism or (less commonly) Taoism, and blend them easily with their ‘native’ religions.
There is a definite strain of mystical, almost Gnostic sensibility that shows up even among those hackers not actively involved with neo-paganism, Discordianism, or Zen. Hacker folklore that pays homage to ‘wizards’ and speaks of incantations and demons has too much psychological truthfulness about it to be entirely a joke.