I think it's cool technology. Depending on the pricing in the end, I would buy a pair to use only for recreation. I can't see myself wearing it all the time.

Where I do see a cool application is as a golf GPS. Over the past couple of years, I've been using an app on my phone for golf GPS that also tracks my score and other related stats. I think it'd be really cool to use Glass as a GPS where it shows you the distances overlayed on top of what you're looking at (eg. distance to the green, bunkers etc). And all this info updates live.

Even though I'm not overly concerned about my data, I can't see using it for anything more than as a toy.

I can see endless applications like those relating to sports. Watching baseball with a live scoreboard and stats. Weather related info for sailing.