If Google disappeared over night I would miss all those documents and it would take too much time to download each doc one by one. Well now Google have added an export feature where you can export all the documents into one handy zip file. Go do that backup today! Here are the step-by-step instructions:
This opens the whole discussion of storing your data in the “cloud”.
Do you fully trust the cloud services you use? Is your only copy of your data stored in the cloud? Would you miss all your email if your email provider disappeared overnight ?