Dropbox

We seldom recommend products but are making an exception with Dropbox.  In the cloud data storage--2GB free and 50GB for $10/month puts it in a very competitive price range with its many competitors but what we like best is its synchronizing features.  Download the little program to all your computers/devices and anything you add from one is automatically synched to all.  And you can access all files from your account at the dropbox site (www.dropbox.com) if you're using a machine that doesn't have the program installed.  Collaboration, file sharing, photo sharing...it's all there and automatically synchs every time there's a change.  Can't beat that!