Looks great but I personally prefer to take notes with jupyter notebook.
For TODO lists I prefer Asana, since it will send you e-mails/push notifications, and has a website + mobile app.
Can jupyter do tables and diagrams followed by code snippets in multiple languages?
Yes. You can use cell magic to change the language for each cell and you can display HTML/latex output inline or just mix computations in with markdown. The only problem is that the editor is just a text box with annoying bracket matching instead of Emacs.
Have yet to try it myself, but allegedly you can run a Jupiter notebook inside emacs:
https://github.com/millejoh/emacs-ipython-notebook
Seems the best of both worlds!
Now, is there a elisp notebook (or is it just emacs)?.