From "Cortical Computing", by Greg Snyder:

A back-of-the-envelope calculation is useful. A human cortex has a density of about 10¹⁰ synapses/cm². Today's microprocessors pack roughly 10⁹ transistors in 1 cm² of complementary metal oxide semiconductor (CMOS). Thus, to build biological-scale neuromorphic circuits, electronic synapses will have to be about one-tenth the size of an average transistor. This is one important reason intelligent machines are not (yet) walking around on the street.

A 10X change in computing is coming. From what I know, the hardware side of this change is going to happen within the next 10 years. But it will probably take a lot longer for the software to catch up.

Also see: DB Strukov & KK Likahrev, 2006. A Reconfigurable Architecture for Hybrid
CMOS/Nanodevice Circuits. FPGA’06, February 22–24, 2006, Monterey, California, USA.