I've no problem with using LibreOffice for most of my document needs, but i haven't found a good substitute for microsoft's OneNote yet. I mainly use it to plan my RPG games and it helps a lot. What alternatives are there for organizing notes on linux, with similar features to those that OneNote provides?
You should check out Affine.pro then. It's FOSS and you can draw anywhere, it's one of their selling points.