I have notes named "Forename" and "Surname" where I put information about the origin and meaning of that name. For example my forename Markus has ancient roman origin and means "dedicated to Mars" which was the roman god of war.
That notes could also be displayed in a special view in Reunion so one can see all the information about a persons name in one view.
I also use notes for "research notes" where I put information that need further research and one note named "Trivia" for all those little snippets that don't fit elsewhere but should be remembered.
I use Reunion and in Miscellaneous notes I create notes of information that needs to be verified or have further research. These I make bold and in blue. My theory or opinion notes I also make bold and red. At a glance I can tell what needs to be done and also explore my theory further. Once I verify what is in blue ... either positive or negative ... the information is either incorporated or removed.
I use the Notes for word-for-word obituaries (including newspaper name and date published) as well as biographies that I write for some of my ancestors. I will frequently put misc. notes in the Notes section, then when I have enough notes, I will format it into more of a story. So far I haven't run out of room in a Notes section, and I have put in pages of copy.
I also list census info:
Year: Address: Occupation
I use notes as others have already said - transcriptions of obits, info that needs to be verified, etc.
One thing that I did do that I haven't seen mentioned: I created a new note, called "Story." I add "story notes" for the stories that are passed down and that I collect from family members. For example, how my grandfather proposed, how a tornado destroyed my other grandparents' house, etc.