I get a lot of value out of taking notes. The process of putting thoughts into words gives me clarity as well as offload threads of thoughts from my mind. I use it a lot for planning too, for every project there's a bunch of notes detailing what's needed and what could be done.
I haven't tried many note-taking apps, so my recommendation to use Obsidian must be taken with a pinch of salt. But it meets the minimum requeriments I was looking for:
Even though it does so many things right vanilla Obsidian still lacks some key features, so I wanted to have a complete list of all the plugins I use in order of usefulness.
Paste URL into selection lets you paste a copied URL into the selected text to create a link. This has to be my most used plugin.
Paste image rename lets you name an image after pasting into a document. It also let's you set a default image name based on the file you're currently editing.
If you organize your files into folders you'll want: Reveal Active File Button, which shows you were your opened file is in your file tree view; and Collapse All which let's you close all the folders with a singe click.
If you use the built-in Daily Notes plugin you'll want: Calendar lets you to intuitively access those notes; and Natural Language Dates to reference them intuitively (i.e. "@yesterday" will become a link to yesterday's daily note).
Obsidian offers a payed service to keep a back up of your vault, although you can use any other back up software like Google Drive or Dropbox. I personally use Git and the Obsidian Git plugin, but I don't recommend this unless you're a programmer and already have it configured in your machine.
Better Word Count to count the characters and words from the selected text instead of the whole note.
Obsidian will try to show you the line where you're writing, but sometimes it leaves you typing at an uncomfortable eye-length, so Scroll Offset fixes that.
Settings Search adds search function to the settings menu.
Copy Block Link gives you a link to a specific header in one of your notes so you can paste it elsewhere.
Advanced Tables adds a lot of functionality to markdown tables.
If you use emoji a lot Emoji Toolbar might be a must for you. It lets you either browse or search for any emoji quickly.
Smart Random Note gives you a random note from your vault based on your query (i.e. you can ask it to give you a daily note by searching for the specific folder).
If you're a programmer: Editor Syntax Highlight to add syntax highlighting to code snippets
Better File Link let's you create pretty links to other files on your computer. Obsidian does this already but it's a bit rough.
Music notation if you're going to use Obsidian for music note taking.
Word Splitting for Japanese in Edit Mode if you have notes in Japanese.
Plaintext to open plain text files that are not in the markdown format.