OneNote is the best Microsoft program you’re probably not using. For me, it's become the online home for much of my work: article drafts, interview transcripts, even random thoughts about how to re-organize the home office.
I love that I can take it with me basically anywhere. OneNote is baked right into the company’s own Surface devices, and there are apps for iOS, Android, MacOS, and support for Apple Watch and Android Wear. It’s not easy to build an app that serves so many different purposes and works well across platforms, but OneNote mostly pulls it off.