In our age of scientific discovery I would like to pose the question...
Why is religion still relevant in out time?
Obviously in past centuries it was a form of mind control and personality cults. Myths and legends to explain our Earth and the Universe and why we were here and to be good people or we shall rot in hell or be reborn as amoebas... but now in the year 2007, why is religion still relevant?
I'm going to address "Western Religion," and Christianity in particular.
I do think Nietzsche was onto something with his "God is dead" thing. We no longer stone people for disobeying their parents, or fear the sword of the "Angel of the Lord." However, that's not the whole picture. Religion is in fact evolving. Just look at changing doctrines towards divorce, abortion, homosexuality, etc.
Religion is always evolving as the worshipers and societies themselves evolve. Religion will never die or be irrelevant, because we're subtly changing it to fit our lives, and to be relevant.
Now, whenever things change, there's going to be a backlash, as change is scary. Change in religion is particularly threatening, as people are so invested in it and things that are "true" aren't supposed to change. This is where you get the fundamentalist back-lash, and that is what you're probably refering to in your post. It's relevant because people need to feel secure. Those are their needs, and what best fits their lives.
Hopefully that helps explain these observations a bit:
Europe used to be Christian, but now it is not anymore. Every year there is less and less christianity around the place. In some citys there is less then 10% of people who can pass as real christians.
There's actually been a resurgence of Christianity within European society. You should read Philip Jenkin's latest book on the topic.