While I lean more to Epicureanism, I do have a fair bit of respect for the Stoics like good ole Marcus, too.
Epicureanism basically argued for a form of materialism, that we have this life to live and that death is the end of it. We should make the best of this life and minimize its pain while looking forward to death as the end of that pain. It also argued that while gods may exist (some Epicureans were basically atheists, other more agnostic), they would be free of the world's suffering and therefore would have nothing to with this world. They were kind of weak on moral theory compared to the Stoics in that they basically espoused a kind of passive hedonism, not actively seeking out pleasure through the proverbial "sex, drugs, and rock'n roll" but rather just from enjoying a simple, somewhat minimalist life. In fact, they argued that the more active, indulgent forms of hedonism were to be avoided as causing pain rather than freeing us from it. So there was no concept of sin or salvation, just a call to live in simplicity and harmony with others, minimize your suffering and that of others, and accept death as the natural end of it all.
