Ok, I’ll jump in:
Apps can be useful, necessary, fun and delightful. Any app can be your favorite. Browsers are useful and necessary (Safari, Chrome, Firefox). Password managers are necessary (1Password). Project and checklist apps are useful (Things, Omnifocus, Todoist). Cloud storage apps are useful (Dropbox, Evernote). Text editors are useful (Drafts, Ulysses, Scrivener). Media players are useful and fun (Netflix, Plex, VLC, podcast apps, music apps). Email clients are useful and necessary (Mail, Spark, Airmail). IRC and VIOP apps are extremely useful (Messages, Skype, Slack, Signal). Productivity boosters are extremely useful (Keyboard Maestro, Launchbar, Text Expander, Bartender). I haven’t even mentioned any games or creative apps (your favorite game or music/drawing app goes here).
My favorite: GNU Emacs! (coupled with Drafts on iOS)
It is the one app that unifies all those useful and necessary apps into one coherent whole. Note taker, checklist-er, list manager, outliner, time tracker, media player, email client, IRC client… not to mention one of the (if not the most) powerful text editors on the planet. What it lacks in looks and polish it more than makes up for in power and features. Need a calculator like Soulver? Emacs has it. Need a full featured outliner and note taker? Need to link an email to a TODO item to a project? Need to track the time you spend on a task? Org-mode has it all covered. Need to export into PDF or docx or epub or html or slides? Emacs does it. Need to write and test some code? Emacs has a mode for it. Need a command line or some file manager-fu? Emacs shell and dired has you covered. Text expander? Check. Want to write a book? Check. Need to track all your file changes? Use magit (a super easy GIT interface).
Emacs has been around for more than 40 years which makes it a living dinosaur of an application. How has it survived this long? It is infinitely flexible and extendable. Don’t like the keyboard shortcuts? Change them. Don’t like the color theme? Change it. Missing a little feature you really need? Write your own and add it in. Need an feature extension? Add it in using a package manager.
Oh, and everything is in plain text. Every. Thing.
Emacs is a living dinosaur. Like a bird, soaring above all the rest of the earth-bound applications. As Neal Stephenson wrote: “Emacs outshines all other editing software in approximately the same way that the noonday sun does the stars. It is not just bigger and brighter; it simply makes everything else vanish.”
Gnu Emacs is my favorite app… ever. It won’t coddle you or dazzle you with icons - rather it will challenge you and make you stronger. You will never be it’s master; but you can be a zen-master of productivity. Forever free and always improving.
There. That was fun!
I went ahead and moved everything over to 2Do, even from Trello. I wasn’t using Trello to its full potential so I decided to cut ties.

Usenet / IRC was where I met my partner.