While you can download documents from Google Docs one-by-one, there’s no "export all" like feature that will let you backup all online documents to your hard drive in one go.
A possible solution is that you select multiple files inside Google Docs browser and export them as a zip but the problem is that files get saved as HTML web pages and not in the standard .doc format.
Zoho has added an Import feature inside Zoho Writer that lets you bring all Google Docs documents into Zoho for editing. The Zoho-Google Docs importer can read .zip files created by Google Docs and hence it can serve as an alternate backup for all your Google documents.
The more exciting part is that they soon will include have a "mass export" feature in Zoho Writer that will let you take away all your documents out of the Zoho system in a click.
Now this should immediately appeal to Google Docs users who have never even tried Zoho yet because you indirectly get to backup all Google Docs documents in three steps:
1. Export all Google Docs documents as an HTML file.
2. Login to Zoho Writer using your existing Google Account credentials and import the zip file created in step 1.
3. Use the Mass Export function of Zoho writer to save these documents as .doc files on to your hard drive or anywhere else.
The export feature in Zoho Writer is not live yet but keep watching this space.