My take on religion (for what it's worth).
Religion is man-made, FAITH is not. So as far as "religion" is concerned, it's understandable that there would be problems, considering the Bible mentions nothing of one "right" religion.
As far as atheists and agnostics go, here's how I see it.
Atheist---believes that when you die, you rot in a box in the dirt and nothing happens.
Christian--- believes that you die and either spend an eternity in Hell or an eternity in Heaven based on how you live your life.
Now, if Atheists are right, and there is no God, then it really won't matter. Christians will die and rot in a box along with everyone else and not much will happen.
Now, if Christians are right, and there is a God, all of the Atheists are screwed and spend an eternity in Hell, "where there will be wailing and knashing of teeth." (As opposed to rotting in a box)
It doesn't take a rocket-scientists to figure out which place you'd rather go. So, IMO, why not believe? If you're wrong, then you'll just rot in box. If your right, then the end result is SOOO much better.