One of the books I've been reading for fun this summer is Karen Armstrong's The Case for God. I haven't read any of Armstrong's other books, but this one is great--a defense of religion that's quite unlike most defenses of religion, including those from the left. For one thing, Armstrong is ridiculously learned, which means that her book ranges confidently through Eastern and Western religions, and their historical developments and intersections. Her essential claim is that all religions (though the Abrahamic faiths are her primary focus) are at their core not about theology, or accepting a specific set of beliefs, but about the attempt to apprehend the unknowable and to live a life that reflects that attempt. In less skilled hands this might boil down to a vague, just-be-nice-to-others-and-go-to-yoga form of spirituality, but Armstrong's book is so deeply rooted in the particulars of different faith traditions that this doesn't happen.
From my perspective, the most important point Armstrong makes is that fundamentalism--taking sacred texts literally--is a quite recent development, and one that emerges out of a desire to hitch religion to scientific rationalism. As such, fundamentalism isn't about going "back to basics" at all: it's an active rejection of the richer and more complicated reading practices (and, Armstrong would argue, of the religious experiences) of centuries of believers. This impoverished understanding of religion also underlies the more dogmatic and crusading of today's atheists, who assume that fundamentalists are, as they claim to be, the only authentic exemplars of religious belief.
There are things to quibble with in Armstrong's book, which is, in its mild-mannered way, polemical and somewhat partial. But it's a refreshing and invigorating read for those who care about religion and the varieties of religious experience.