I use emacs org mode and it's superb (not applicable to general populace, I know). Mobile is not that great, but I always carry ultrabook with me.

I use keep. It is already there on all platforms i use and integrates with other services i use. Plus the location reminder stuff does not drain additional battery.

But honestly since i dont use it anymore i feel better and more relaxed. Relevant stuff i dont forget and irrelevant stuff is irrelevant.

Checkout "Notebooks 8" for iOS. It is the ultimate note taking app.

>> Note taking done right. Android, iOS, Desktop

> Checkout "Notebooks 8" for iOS.

Might be good but misses several requirements :-)

> do this all without wasting whitespace (no doc editor like Evernote)

What do you mean by this? Do you just mean a raw HTML/markdown editor and a rendered view?

I mean that notes (at least for me) tend to be short. What I don't like is that many note taking systems think that a note needs to be edited like e.g. an Email or Word document (the Evernote approach). So when I see e.g. 10 notes I want to see the most of the content of the 10 notes very good and when I go into one note I don't want to see a whole big word processor with one blank sheet. Google Keep is doing a good job there, also not bad is e.g. Tiddlywiki.

Simplenote gives you the ability to take notes in markdown and be able to view the rendered version by swiping right.