I was raised Roman Catholic (baptized and confirmed) and discovered Witchcraft (from Wicca and Druidism among other sources) at age 13. Since then I continue to study many of the religions/philosophies/belief systems of the world and have taken the parts of each that resonate within me and combined them to create my own religion/philosophy. This includes Shamanism, Pantheism, Paganism/Neopaganism, Buddhism, Daoism, Hinduism, Sikhism, Animism and Shinto among others.
I do this too! It seems like every religion has aspects to it that are worth knowing and respecting. Unfortunately, it's usually only an aspect, and any given religion seems terribly corrupt on the whole.

I was raised Roman Catholic as well, but I don't believe in any of it (in fact most of it disgusts me)! What I gained, though, is a deep respect and reverence for the concept of forgiveness. Unconditional forgiveness is central to my personality, and I couldn't have done it without Catholicism.