Since creation of GMail there have been many questions and ideas of how to use GMail for uses other than eMail... One of my personal favorites have just come to light...
I've known of the possibility to use GMail as a file server (much like the Yahoo! Briefcase) in many differant forms (mainly Telnet and various web scripts) for a while now, today however I found a Windows Extension which allows seemless integration into GMail through Windows Explorer.
There are some various small issues with moving files to your GDrive, such as the 10MB limit (this is a limit set by Google as the maximum attachment limit). I however have fallen in love with the ability to upload various rar files to my GDrive and have the ability to check them from anywhere in the world just by logging into my GMail account and checking my "FServ" label for my files.
Checking your files through GMail is as easy as looking at the email created by the shell extension client on your computer (mine i have a filter configured to label the message into my "FServ" group and archive the files) and click the subject associated with the file (for example paris_hilton_phonebook.rar) and at the bottom of the message you'll see the size and a download link to download the file as you would with any attachment. Additionally you can also use the Windows Shell Extension to list and maintain your files.
This is the best GMail "hack" (or addon) that I have personally seen and saves a lot of time (as the 1GB space from GMail kicks the crap out of any other provider that offers file space).
To read more on this shell extension go to: http://www.viksoe.dk/code/gmail.htm