In order to live in an Android/Mac/iPhone/Web based world, I had to switch from my beloved OmniFocus over to a new todo application. What I ended up settling on was Todoist — an elegant, eminently cross-platform, and generally simple task manager.
The major failing of Todoist compared to Mac-specific todo lists is its lack of integration with other apps via services, LaunchBar, etc. It has a powerful API, but no local AppleScript support for proper scripting.
Enter these scripts: using the excellent JSON Helper for AppleScript as a support tool, I have put together two critical pieces for my workflow: An AppleScript to quickly add a task via LaunchBar (easily edited to support Alfred, Quicksilver, etc.), and a Service that lets me clip text from any app and create a to-do.
Due to the need of integrating with web services and providing useful notifications, these scripts require the free JSON Helper and the inexpensive-but-critical Growl. They will also only function if you are online since they rely on Todoist’s web API.
Prior to installing/using these, you will have to open each item in AppleScript Editor and Automator (as appropriate) and add your API Key from your Todoist settings.
As a special bonus, I have also included an AppleScript file that contains a subset of the Todoist API suitable for copying/pasting into your own scripts for further Todoist automation.