I want, desire, NEED, a task manager that works with Mac OS, Android, and iPhone OS. I've been using Remember the Milk for a while, and even paid to be a Pro member, but I hate the Web interface so much that I can't convince myself to keep using it.
I've used RTM, Toodledo, Things, OmniFocus, TaskPaper, and Google Tasks. Liked them all, but most don't have the Android sync, which I need because my Android phone is with me 24 hours a day. I need offline support, easy and simple (preferably OTA) sync, and, most of all, a great interface on Mac OS – that's where I use task managers 80% of the time, and that's where RTM falters for me.
(Also, I tried a Greasemonkey script for RTM called "A Bit Better RTM." It rules, but doesn't work in Fluid apps, which is where I want to use RTM.)
I don't care if it's an improvement on the interface for one of the web-based managers, or an Android app for Things, or whatever. But if you make this, tell me. How much will I pay?
I will pay infinity dollars for this, to anyone who pulls it off. And I'm betting I'm not the only one – just check the forums for any of these apps. Please please please!