My pal takes on some silly ad campaign trying to convince us heathens that God is realz0rz, and is also Jesus. He makes some good points - I especially like his refutation of the anthropic principle (though no one can best Douglas Adams' puddle analogy). I'm not going to approach the subject that my good friend Noisy Queer Vegan covered, as he's taken care of that quite well indeed, but I will go off on my own tangent..
Since I've recently moved to a new location and am surrounded by people who don't know me well, I've gotten to explain why I'm a deterministic atheist to a good handful of fairly educated, non-judgmental people. I think it's gone down well, and I've learned how to succinctly explain what I believe and why.
Basically, what I think is that the God-belief-thing is really statement about what a person believes is the nature of the universe at its most basic level. If you take away all the matter and the energy and the spacetime (if you can do such a thing), what's left? In a theist's conception, the basic and default nature of the universe is an infinite consciousness, with desires and thoughts and feelings, which can create and destroy through sheer will.
That seems pretty damn unlikely. And it certainly poses more questions than it answers. From what I understand about how reality works, things start out simple and then, over time, things develop progressively more complex emergent patterns. A very simple "first cause" would require a lot less explanation for its own existence than a very complex one.. and I can't imagine anything more complex than the infinite consciousness that I described above.
Thus, I do not believe in a God. I am not sure what exactly the basic, default state of the universe is (my best guess - empty spacetime?), but I can say with confidence that God ain't it.
In sum: Ultimate 747 + Occam's Razor = o'rly.
BTW: I got to where I am, philosophically, from watching Scott Clifton's vlogs. I may or may not be desperately in love with this man.