What you choose to believe comes down to you, and you alone. I've been going through my own personal trial of faith, and though my circumstances are much different than yours I can say it's not an easy thing to go through. I can say, however, that questioning your beliefs, whether you're a believer or a skeptic, is healthy and everyone should keep an open mind about both sides. It's important to have an accepting attitude of beliefs that directly oppose yours, or you're only going to make things worse for yourself and for your family.
So there's a few things you need to do.
1) Try to understand the "other side".
Judging from your post title you have a very adversarial opinion of religion, and that's just as dangerous as a religious guy thinking atheism will destroy the world and hating all atheists. You need to accept that people will have beliefs that are opposed to yours, and that this doesn't make them dumb, gullible, or whatever. You should make every effort to understand where the other party is coming from, and admit that it makes sense from a certain perspective, even if it's not for you.
Understanding and accepting dogma that's opposed to your own beliefs requires a great deal of empathy and effort. Don't think that you're going to suddenly be converted back to something you don't really believe in just because you're opening your mind to other possibilities. Heck, lots of staunch atheists have read the bible and lots of faithful Christians have read the God Delusion and I've yet to hear a conversion story from either side in those circumstances.
Understand that actions and beliefs often don't have a lot of bearing on each other. There's lots of dumb Christians just as much there's lots of dumb atheists. Everyone's capable of making a bad decision, no matter what they believe. Avoid the temptation to think that someone does something purely because they believe a certain thing.
Understanding why people feel the way they do about beliefs that conflict with their own is very important in cases like yours. If you continue feeling like your parents are the enemy because they hold a different view than yours you're going to have a bad time. You should be open and understanding of their beliefs as you want them to be of yours. You can't possibly expect them to accept your decisions if you don't accept theirs. It's not fair, and it's certainly not going to earn you any points in the "Please don't punish me because I'm thinking about becoming an atheist" category.
Which brings us to point two.
2) Open up to your parents.
As in, sit down and tell them that you love them and respect them and all that jazz, but you're having a bit of a conflict of faith right now. It's probably not a good idea to jump up one day and say, "Mom, dad, I'm an atheist!" Start with delicate questions, like "How do we know that God exists", "If I'm not 100% sure God exists will I go to hell", stuff like that. Best not to mention atheism directly until later, maybe much later.
Depending on your parents, it's going to be a delicate dance. If they ask if they can help, tell them you need space and time and don't want to feel like you've been forced to a decision. Promise to pray and read the bible, and actually follow through with it if you're comfortable. Never hurts to try. Exactly how much you tell them and what you promise to do is up to you to decide, just remember that these people probably thought that their child was a faithful teenager not five minutes ago. They may be sensitive about having their child question what they've been teaching him. Do your best to make them think you're going to do all you can to make the right choice.
Do not. DO NOT. Do not be angry or confrontational. There's no way that you're going to convince them that God isn't real. You may be tempted to hurt them in order to make your point if things turn sour.
Don't do that. It would be incredibly dumb. It's not a competition. Your parents love you and want the best for you, but if they think this crisis of faith is going to turn you against them, you're definitely going to lose points in the "Please don't punish me because I'm thinking about becoming an atheist" category.
Be open, understanding, and loving, but be honest. It probably won't be easy. Stamp out that anger and self-righteousness and put on a humble face. These people are your parents and deserve your respect, and if you give them that love and respect, and show it in the best way possible, they're a lot more likely to respect you. Try to take any advice they give you sincerely, even if you don't find it palpable.
Act like an adult, be treated like an adult.
If things turn sour and they react badly, we can talk about that then since from there it's mostly damage control on your own feelings. Which brings us to the final point.
3) Come to terms with your beliefs (or with what you don't believe).
With the those "understand the other side" and "talk with your parents" things out of the way it's time to sit down and figure out, sincerely, how you feel. If the first two points were hard, this is going to be the hardest. You're questioning beliefs that you've been taught your entire life. How you feel about and see existence itself is on the line.
Take a philosophy class, if your high school offers it. If not, just read about it online. There's been a lot of thinking done about the nature of existence already, so lots of dudes have done the heavy lifting for you. Read about different religions, read about atheism. Figure out how you feel. Keep an open mind. Keep on trying to accept others for who they are, no matter what they believe is out there.
Reaching a decision and coming to terms with yourself will probably take years. Even if you never figure things out for sure, all the research and thinking you've done will do you some good. You'll come out on top if you do things right, no matter what you decide to believe.
Good luck.