insync supports a lot of DE, such as KDE, GNOME Shell, Cinnamon, Mate, XFCE, Applet, and KDE Plasmoid, but since i used KDE on daily basis, i will only provide you with the KDE version. You may modify the script to work with other DE if you like.
When you started your application for the first time, it will ask your permission to connect to your Google account. When you granted the request, it will start syncing your documents and placed them on your /home/
Insync also allows you to sync multiple account if you have more than 1 account.
This is a BETA version, but i found it quite stable in my own experience. Try it if you need an offline editing of your GDrive documents. This application is also available on Windows and Mac OS X.
Update (6:35 PM): Big thanks to Marcel Sägebarth for testing in x86_64 machines. The problems in those architectures are now fixed and the script has been updated. Please make sure you get the latest revision (currently it's build identifier is 4wsr per January 29 2013)