I use Outlook Notes for books to read, "how to do a certain something", etc. I will also put links in Outlook notes, if I want to remember where on the internet or on my pc I can find certain resources, for example a list of potential outsources for widget designing, etc.
Otherwise, I have reference file folders for non-digital documents, such as brochures for where to possibly go on a vacation. A vacation checklist will probably be in my notes or a print-out will go in a file folder with other vacation stuff.
In my organizer, I have my various checklists, such as my weekly review. I only keep vital information in my organizer, such as passwords and important checklists, since I want a clear overview at all times.