I was thinking of making an app like this in the past. To take it a step further, I actually thought (still think) it would be cool to have a heat map of your entire life across the whole globe. Battery life issues aside, I decided to scrap the project for inevitable privacy concerns.
Build it. People who worry about the privacy implications just won't use it...
As someone who travels a fair bit, I think it would be really cool.
I also had this idea some time ago. I thought it it as a rescuetime for life, and actually reserved the domain lifelytics.com
It would be fairly easy to build on iOS. I had a similar idea a couple months ago, and started to build it last night.