I'm on Mac OSX and almost all my non-programming files are in /Downloads. Maybe some other HN-ers have a better folder management technique than mine (which basically is absent), I'm curious what that is.
Anything of importance, I have broad directories under Documents, and then sub folders. Or sometimes I'll put them on my fileserver with similar directory structure. The Documents folder is backed up with Spideroak.
But I struggle to follow a consistent structure, so it could be in Documents or Notes, or a random folder somewhere else because I ignored my hierarchy in a hurry.
Honestly, now if I need to make sure I keep something, I upload it to Google Drive. It sucks for privacy, but their search is good enough that I rarely need to use the hierarchy. The hierarchy is now mostly to group things I want to perform actions on together.