I think about AI a lot. Read about. Write about. Masturbate to it (sexbots... Mmmm yeah). I still think that building AI is going to be impossible.
I look at it like a tree. Yes, we understand the basic model of a tree. We know where parts go in relation to one another, how the systems work, etc. But still, we can't build a tree from the top down. We can't engineer branches here, and leaves there. Because even though all trees are pretty similar, they are also wholly unique. Defined by the manifold variables to which they are exposed as they grow.
Instead, we start with a seed and let it grow. We know the primary, fundamental variable required to grow a tree, the seed, but we cannot construct a tree artificially. I think the various learning robots being created, where they respond to and learn from their environments, are the first steps in the creation of non-biological intelligence.
I use that term because I don't consider them artificial at that point. They've grown of their own action. Yes, we created the stuff at the beginnning, but that's like calling a GE ear of corn artificial corn. It just doesn't make sense. It's non-biological, but it has grown naturally, in the same way our own intelligence grew.