I just use a file in Dropbox. That is devastatingly effective for me - available across devices and offline.
I keep notes in text files in my Dropbox -- on desktop, I use vim or SciTE, and on iOS I use the PlainText app to read/edit them.
How do you structure your dropbox file? Is it a simple running list of tasks? (.txt)
Just two files forces me to prioritize within these two spheres.
Thanks for sharing!