I think these 'wearable computing' devices are getting hyped too much even before the products are shipping.
There might be some future in them, but I don't think people should expect too much. In the end, the devices have to be really functional to be succesful, and I think that can be a stretch.
I mean, Google Maps on your glasses is nice and all, but it seems like a niche. A watch is a perfect device for displaying the time, but for anything other than that it might become clumsy.
I don't think we should expect glasses and watches to become 'the next revolution', but more like an addition to the current smartphone. They're main advantage is that they're closer to you, you're already wearing you're glasses and your watch is just one look away, thus eliminating the 'getting your phone out of your pocket'-interaction which can become tiresome. This means they're perfect for serving as a second display along with some minimalistic control options. But the phone should be the hub.