Tumblr is a free blog hosting platform offering professional and fully customizable templates, bookmarklets, photos, mobile apps, and social network. If you have a blog at Tumblr you can now backup the complete data easily as backing up your files is one of the most important needs. Tumblr Backup is a nice service which allows you to backup and download your Tumblr blog including your photos, your conversations, reblogs, and favorite quotes.
The service is not yet open to public, but is expected to launch soon. Once you have authenticated your Tumblr account you will be able to download the complete backup. You can even use this backup to import the files into a WordPress blog if in case you want to shift platforms.
You can access your Tumblr files even when Tumblr is down or not accessible due to maintenance. The service is not free, but costs you $9.95 for one blog. Considering how popular Tumblr is the service is pretty good in its form. You can currently sign up to receive updates on when the service will be live.