Dropbox is an incredible file-syncing tool. Say goodbye to clunky usb-disks that you forget, and say goodbye to trying to remember which of all the versions of a file is the latest one.
Dropbox solves that by putting an always synced folder on your computer. Now you can get to all those files very conveniently on your Android phone. You can also edit text files right within the app.
And since Android is such an open system you can open nearly any document (whichever format it is) with the app of your choosing.
You can also upload photos and videos taken with the camera right up to a folder in your dropbox. So it's really easy to instantly share things with your friends, family or colleagues.
To sign up, and get 2.2 GB of space, use this link: Dropbox.