There's a great post on "Scharnetzki’s line of reasoning" about using OneNote to manage projects and tasks. The way he describes his workflow is almost exactly how I manage mine. Using a notebook section as a project folder works perfectly for me. I can push an email to the proper project folder with a push of a button (see his post for details. Using pages and sub-pages I can easily find emails, quotes and copied web-pages germane to the project.
My only difference is that Scharnetzki seems uses the "to-do' tag in OneNote to keep all of his tasks together, but also keeping his tasks in OneNote. I use Outlook as my work "dashboard" and all of my tasks have to end up there. I want all my tasks in one place where I can see them. Fortunately, OneNote and Outlook synchronize bi-directionally making it moot where you put your task!