Google Drive - The new name for the repository of Google Doc files - access them all on your device. iOS editing still isn't great, but the Android version has great reviews.
Dropbox - Sync a folder on your computer (and another computer), with your devices and the web. Gives you access to every file in the folder.
Organizing and Sharing Content
Evernote - Create notes by typing, voice, and photo. Store them in notebooks that can be shared. Access and sync your notes via the web, desktop browser, or mobile device.