I'm a big fan of taskwarrior, a CLI todo list for linux. I find I use it more than web based ones as I'm always in the console so there's little mental mode switching to use it. Basically not having to go to a browser or touch the mouse makes all the difference.
I'd love it if someone made a todo web app that could sync with taskwarrior. You then get the online slick interface of the web app with the low friction accessibility of the console interface when in the zone at work.
Yeah - this works well and there are no catches. The data is in a few human readable files and there's a path in the config file (.taskrc) pointing to the directory where they live.
So you just move the data folder to your dropbox and edit your .rctask file accordingly. Of course you need to do this for every computer, so it makes sense for the few machines that you usually use but you don't really get the available-anywhereness of an online app.
I'd love it if someone made a todo web app that could sync with taskwarrior. You then get the online slick interface of the web app with the low friction accessibility of the console interface when in the zone at work.