We have previously mentioned a few ways to back up your Google Docs files. However, the tools and methods we mentioned previously worked for a limited number of scenarios. Gladly, there is an application now that will work for everybody.
GDocBackup is a freeware utility for Windows and Linux, that lets you backup your Google Docs to your local drive. After you have downloaded and installed GDocBackup from here, it will prompt you for your Google account details. Once you have entered your user name and password and specified a folder location, GDocBackup will download all your files from your Google Docs account.
You can also specify the formats you want to download your documents in such as downloading presentations as PDF files. After the first backup, each subsequent backup will only download the new files that have been added to you Google Docs.