Wherever possible, I use plain text files for everything - note-taking, coding, writing, etc.
My operating system of choice is ubuntu, so I use the wonderful nvpy, a notational velocity clone, for all my quick notes, from things my daughter said I don’t want ever to forget to ideas and tasks etc. But how to get the same notes on my Android phone? In theory nvpy syncs with simplenote, which has an Android client, but in practice I had endless problems with the sync, perhaps because I have quite a lot of notes with funny characters in them. So I switched off the simplenote sync, making nvpy use just a big folder of plaintext files, which is the way I like it. But again, how to sync with Android? After a lot of messing about, I have finally found Minutes Notes which syncs effortlessly via Dropbox with my nvpy folder on my desktop, and has plenty of other features for geeks and non-geeks alike. Problem solved.