I use OmniFocus. Every once in a while I look for something "better" but decide that I just need to be better at using OmniFocus. That is probably true for any of the todo list apps.
I've also been sticking with OmniFocus. It syncs to each of my Macs and iOS devices, yet it still accepts changes when offline. It offers a quick-entry "inbox" but also two higher dimensions of organization, project and context, when my inbox inevitably grows unwieldy. It supports recurring tasks and due dates for important reminders like credit payments.