I'd like to make what I feel is an important point. You appear to set up a mutually exclusive relationship between God and science, and it is this common misunderstanding that places science education in this country in great peril.
Believing in God and believing in science are not mutually exclusive at all. They are two fundamentally different endeavors. Science does not apply to all pursuits of knowledge of all kinds. Science is sort of like 20 questions. If you can put forward an hypothesis that can be rejected, that is falsifiable, then science can answer that question. But if the hypothesis cannot be falsified, e.g., H: God exists, that hypothesis is outside the realm of science. It doesn't make the hypothesis false, necessarily. It simply makes it out of the reach of science. Many religious questions, most philosophical questions, etc., are all beyond the reach of science. Doesn't mean the answers to those questions don't exist, just means that science can't answer them.
Therefore, people can believe both in science and in God. They are two completely different realms of inquiry, two completely different realms of truth. Now, sometimes, the two overlap. Some people's religion dictates that they believe that evolution doesn't happen, when in does and it has according to all the scientific evidence we have. But what about the question, "Was God in charge of evolution?" Science can't answer that one. Since a God would be omnipotent and not bound by natural laws, hypotheses about God cannot be falsified.
You, personally, can choose to believe only those things that can be disproved, that is, only things that are answerable by science (nothing can ever actually be proven in science, things can only be disproved or found to stand up to lots and lots of testing so that we think the hypothesis is surely correct). But that, actually, is a choice of what to believe that is not based any more in logic than another person's choice to believe in things that cannot be disproved (God).
I, also, choose only to believe in things that can be answered scientifically. But if you make that choice, you cannot logically conclude that God doesn't exist--you can only conclude, like science does, that we don't know, because the answer cannot be found scientifically.

This, my choice to believe as firmly in science as I do (actually, for me it's more of an inherent way of being more than a choice, I think) is what makes me an agnostic. And yes, to answer another poster, I also think that aliens might exist--there is no way for us to prove that they do not.