I've argued elsewhere that secularists should turn to existentialism and to pantheism for any so-called "spiritual" needs. "Spiritual" is an archaic way of speaking of our existential condition (of being mortals struggling in an indifferent universe). In the article below, I argue explicitly that existentialism should replace spirituality.
But the question you're raising is whether there should be an atheistic religion or sense of spirituality or existential depth. Ask yourself what an honourable, viable atheistic culture would look like if that culture were to lack any sense of sacredness or of anything's ultimate importance. Chinese materialism or pragmatism gives us a good example, but whether that kind of secularism is respectable in existential terms is another matter.
