There is
Microsoft Office 2011 for Mac. You can get it from Titles at a discounted $94.99 (or thereabouts).
There is no Microsoft OneNote for Mac. However, Word has a
Notebook Layout which makes it really easy to take and organize notes by subject and topic. It has notebook-like tabs so you can take notes from multiple topics or courses in one document.
Also, you can record audio with your notes while you're typing, and it'll display an icon at the position on the page where you started recording. Essentially, you can voice-annotate your notes, and synchronize the flow of your recording with your notes.
However, it is the general consensus that Pages is better than Word. It doesn't have any of the notetaking features like Word 2011, but in terms of ease of use for layout or just regular typing (for essays, etc.), it's a lot better. Same goes for Keynote; in fact, it blows Powerpoint out of the water. It's only Excel which beats its iWork counterpart, and OneNote, an amazing piece of software for which there is almost no replacement.