I recently read someone make the bet that there will be GPS-enabled powerbooks before G5-powerbooks. I would agree. Moreover, here are some example uses for spotlight that include how such functionality would be really useful for archiving/searching for files. In their example, he poses your powerbook would know both when, and where you wrote/received documents. You could search for "presentations written in Omaha", or even locations "photos taken at home".

Of course, this functionality is available immediately. One could have a cumbersome plug-in GPS received, or even better, a bluetooth GPS receiver that is constantly tracking your laptop (well the receiver's) position. When a line-of-sight to the sky isn't available, the meta-information could contain the wireless access point name the laptop was connected to when the file was written, or even use geolocation-by-IP-address. :)