I'll try to keep this short and simple.

To compare Atheism and religion as a whole.

If you're an atheist and believe that when you die thats it, you're done, nothing, *insert strange dream philosophies here*, and you think that everything just stops for you. What if then you died, and you stood before the Almighty and he said "why didn't you believe in me?"

The point is.... what do you have to lose in life? NOTHING! But in eternity? you have absolutely everyting to lose. So why not believe?