Well.... Netoworks are pretty much in the Ethernet world right now, very much in the 100Mbps and migrating more and more to the GigaBit technology, in fiber or cooper.
I think this speed will keep increasing for wired networks.
There is also the wireless networks, reaching speeds up to 54 Mbos for the WiFi technology, and the WiMax is coming closer to realese, but i really think the wireless netowrks wont pick up cause the bandwith is just to much great to get the speeds a wired network can offer.
What i think is the future of networks is the fiber optics field, more and more the networks are migrating for fiber optic, not only for backhaul and stacking but for reaching servers and in the future with the coming of fiber to home and ethernet firber adapters i think it would be the leading technology. I would put my money on fiber.
Hope it helped.