monist or dualist?

I’ve been reading ‘The God Delusion‘, by Signor Dawkins. Prior to reading this book, I’ve only read articles and summaries of his work. This is much more of a full digestion of his work.
To be honest, and this is based on some terrible reading in my youth, I’m a monist, with slightly dualistic tendencies based on being able to use some mechanical system to replace/reproduce someone’s mind. Let’s be honest about this; I think it’s only a matter of time before we create a mechanical system that can replicate actual people. The why question is, of course, is this the same person?
If you recreate the exact mind of another person how can anyone determine after the fact that one is different from the other; in fact as a recreated being how do you know that one is more than the other. Consider if you replaced someone’s brain one neuron after another is there any difference?
Honestly, this isn’t a god question, it’s not about god, it’s more of the nature of existence. Whee, I can back myself up, what does this mean for my mind in the future?
Pants, I’ve just put into words something that has been sitting on my mind for a long time.

Sorry kids, I don’t believe in a god.