you can either believe in something or nothing. nothing you believe in can be proven true to someone who doesn't believe in it.
the root of all theistic debate is that we can prove anything and everything to be wrong, but we can't prove anything right.
believing anything will appear irrational to those with different beliefs. but believing nothing collapses your universe into nothingness. hence, i choose to believe something. and to all of you who believe differently, i appear irrational.
anyway, for the record, i believe in god, and i choose to be irrational about my belief. because i feel i'm incapable of reducing my beliefs to rationality, and i'd rather have a name for my inspiration that makes it seem greater than myself. also, i can see that the concept of god has given rise to the concept of religion and the social structures arising from it. and since these social structures have personally done me good, i choose to acknowledge them, and follow them whenever they appeal to my sense of self-preservation and happiness :)