Now, what’s about other options?
Dropbox is a must-have application, especially if you need to share some files with specific collaborators and keep trace of any changes related to those files; CloudApp allows to share images, links, music, etc.: it’s like a remote iTunes/iPhoto and as such includes so-called Raindrops which are small sync service with common multimedia applications on the Mac;
Syncplicity is an alternative to iWork.com and can be linked to your Google docs;
Evernote is a versatile note editor, allowing to sync images or text (and even audio recording) between your iPhone, your on-line web interface and your Mac.
Most of them are available on iPhone too.
I discovered Dropbox at the beginning of 2009, and used it a lot since then. The latest beta version (available on the experimental forum build) offers several improvements, including selective syncing and getting a shareable link for any of your folder (and not only the Public folder). I am waiting for the release of Elements which promises another great enhancement to Dropbox.
I also discovered Dropzone which is an application/script launcher sitting in the Dock. It offers useful shortcuts like URL shortening through bit.ly, upload to your Fickr account, sharing snippets (gist) on Github, etc.