I believe in God. However, you are acting very far from a true Christian right now. You should never insult others, specifically their religious choices.
To them, their choice makes more sense than ours to believe in God and Jesus Christ.
Buddha is not a god. The Buddha is an example of those who reach enlightenment, those who are released from the constant cycle of karma and reincarnation. There have been several Buddhas, the big jolly one is only the most popular.
Allah is just a different name for God. Muslims believe in a single God, as we do, but they believe in more strict practices than most Christians do. The rituals and histories are different, but the end result is the same: be good to others and do good things and pray to God, and you will be rewarded. Do the opposite of that, you get punished.
Christianity and Islam are very different in many ways, but compared to other religions, they are very, very similar. Do not get a bad taste about Islam because of the radicals and terrorists...most Muslims are quite the opposite of those.
Just like in Christianity, we have some people that give us a bad rep too.
God is great, but you need to be a little more open to thy neighbor.