This thread makes me think back to when the Apple rumor mill was brewing about the iPad - or iSlate - or iTablet... or whatever the rumor mills were calling it at the time. I was an avid user of another forum, and I posted on there the day that the iPad was available for order, that I ordered one for my wife. And the thread took off, and dozens of users laughed and thought I was an idiot for spending at the time, $600+ on an iPad when the primary use would be for my wife to read her books, surf the web and check email. Nearly all of the haters said I should've bought a $200 netbook or $500 notebook, etc. etc... I look back now, and my wife is still using her iPad (1st gen) nearly nightly. She loves it. She bought me the iPad2 when it was launched, because there was times when I would ask her if I could use hers! LOL
So the Google Glass... I don't see a particular use case for it at this stage... But I think if they get the display technology and GUI nailed down... Then it could definitely be a game changer. There are a lot of apps - like driving mode that I think would be useful. Especially if they were able to overlay a GPS map over what you were looking at - out of your cars windshield. I think that would be cool. I have a GPS in my car, and the GUI is not great. The car is a 2008, so I'm sure GPS GUI's have advanced since I bought the car, but I hate how the exit ramps are done - especially when you have an exit you're unfamiliar with - and you need to exit right - but then merge into the left exit lane as there are more than one exit on the same ramp. That is always confusing with the way it is displayed... And things like that could be improved by Glasses IMO.
Personally, I hope these type of devices take off... Because we need to continue to push the edge on mobility and personal computing (says the guy in the technology sector).