Atheism might sound like it makes sense but really all it turns out to be is hopelessness. Imagine a person in bondage or suffering being told when you die that's it then what's the point of living? People keep living each day because there is a hope that there is a better tomorrow, that what they suffer is to teach them something for the next life. Take away that and then what is life worth?
You feel like you need to believe in something after death to have hope? What a sad life that must be.
Agnostic rather than true atheist, but close enough for this purpose. I find hope in this life, I find purpose in this life, I find meaning in this life. If there is an existence after this life is over, that may or may not be good (Frankly, I find the concept of there not eventually being a final end to be horrifying, no matter the environs.), but I will have actually lived before the end. I cannot say the same of many Christians who placed far too much hope in heaven.
Ultimately, an atheist is inclined to find hope and purpose exactly where he is, if none can be found, the remotely intelligent among them are inclined to create it. A devout believer on the other hand is inclined to place hope and purpose in something that may never come to pass, and neglect their life in the only life they can be certain they will ever have. I'll take the former behavioral pattern thank you, and adhere to what I consider a good ethical code along the way.
And then of course, all that pales in comparison to the principle issue. We're talking about belief, not a political party. One cannot change banners on a whim. I quite firmly do not believe in the Abrahamic god in particular, and am only halfway convinced that a deity or other supernatural entity MIGHT exist. No matter what you say to try and convince me my life is less worth living than I find it to be, I'm not going to suddenly start believing. I couldn't if I wanted to.