TODO apps were amongst the first things I installed on my android.
There's many good TODO apps, with all kinds of UIs and features. The first one I stuck with was Astrid, because of it's widget. If I have to remember to open an app to know what I have to do, my tasks will remain undone. And if a widget's an eye sore, there's no way I'll keep it on my main desktops.
My pick's something I discovered during the last apps sale, named simply Tasks.
Tasks sync with google tasks and let you manage multiple accounts with multiple tasks lists. It also offers a great widget that's got a clean look and that not only let you see your tasks, but mark them completed without having to open the app. And it offers two themes, white and black, the black one having a transparent background. I just love transparent stuff on my desktops :)
Another thing that shines by it's simplicity is it's manual sorting. While automagic sorting based on priority, deadline and other factors might seem interesting, it's never quite right. Much better to just sort it your way, and adjust it as your priorities change.
