One of my friends, who is a Christian, once asserted, essentially, that without God, life is meaningless. The thing is, though, meaning (to use a synonym, purpose) is created whenever an optimization process, such as evolution or a sentient being, uses something. If you're a big fan of your genome or Darwinian philosophy, spreading your genes is your purpose. If you're the only doctor in your village and everyone comes to you for medical help, that's your purpose. An omnipotent guy doesn't have to tell you your life has meaning for it to have meaning.