I have tried countless task management/schedule apps. Until recently I was using iProcrastinate (don’t get it, not worth it), but I just found Wunderlust.
You can download this app for free on iTunes. It is available on your phone AND your mac.
The layout is simple, and the app is straight-forward and easy to use. If you aren’t a Google calendar person, like me, then you’ll probably be surprised with how useful Wunderlust is.