Mac only: Previously mentioned open source FTP client Cyberduck has just released a new major version, featuring Google Docs uploading and downloading, image-to-Google-Doc conversion, and a Reduced Redundancy Storage option for Amazon S3 storage.
The Google Docs support alone is a pretty neat feature; you can upload and download documents straight from your Docs server from your desktop, either as a storage measure or converted to Google Docs format. And, as if the regular Docs support wasn't enough, you can also upload and convert PNG, JPEG and GIF images to Google Docs as text documents, using Optical Character Recognition.
Cyberduck 3.5 also adds a few more minor features to its recently released Amazon S3 support, including plain text connection support, support for SecurID passcodes, and a Reduced Redundancy Storage option that reduces costs by storing less important data at lower levels of redundancy. Click here to read the full changelog, and hit the link to download the new version.