You're right that note-taking will be one of the killer apps for the next generation of tablets. OneNote for Metro ("OneNote MX") is already available in beta, so I'm guessing Microsoft is chasing that:

http://apps.microsoft.com/webpdp/en-US/app/onenote-mx/f02238...

http://www.winsupersite.com/article/office-2013-beta2/office...