Mostly I use Geany, which is a pretty straightforward, but also pretty powerful text editor. It has nice things like column selection, tabs, and a built in terminal emulator. If you're familiar with Windows it's kinda like Notepad++.
I guess QOwnNotes counts too! Which I use a lot for organising notes. I always have it open.
Otherwise I use Vim (and sometimes nano) a bit when I'm working in a terminal environment, but I really don't need to take advantage of most of what it does.
I really enjoy learning about interesting Vim features and have romantic ideas about learning GNU Emacs (especially org-mode and acme, but that's more just out of interest than any practical need or want for efficiency.
These are the features I look for in a text editor:
Ones I don't really care about:
Terminal-based, contemporary take on a Vim-like modal editor?
Calling it a 'A post-modern text editor' really bugs me though! BAD JOKE.
Plaintext + line drawing (stored as json)