Though I don't subscribe to any one organized religion, I think many people would find me to be more spiritual than many people who say they're “believers.”
It's not that I need to talk in new-agey terms about astral planes and chakras — such talk, while better than the cliches of Abrahamic religions, still majorly turns me off.
Rather, I can explain life in simple language; language we use every day — because life is what has taught me, and it's spoken the language I speak. And to be able to learn its secrets today (not from a 2,000 year old book), I think, is the best way to learn about eternity. I don't need to read an ancient book to understand life today. Of course, reading texts from history helps put things in context, but for the rest, this very moment tells me everything I need to know. And comparing the old and the new shows that existence itself doesn't ever change. People are still born and eventually die. They breathe the same things; eat, drink and reproduce to survive.
There's nothing that tells me I can't rely on my current, real, live existence happening right now to tell me all I need to know about how to live a good life or be a good person — by living with a bit of wonder I can learn it all.
And I think that's how it should be. Man, woman, dog, cat, bird, dolphin shouldn't have to “believe” that something exists (e.g. the afterlife, good and evil, etc.) as a prerequisite for eternal wisdom. If the wisdom is true, it will be evident in our very own live consciousness, right here and now.