A to-do manager doesn’t fit into everyone’s life—you’re probably just as likely to delete these apps as open them a second time. Any.do is stickier than most, though. Any.do plugs into phone functionality like the calendar, phone, and messaging app so you can execute actions without opening any other apps. Any.do also supports attaching files to items that are synced across devices. The black AMOLED UI is right there in the main settings page. If you really dig Any.do, there is a premium suite with features like unlimited attachments, passcode protection, and a raft of others. If you're willing to cough up a monthly subscription fee.
Any.do (Free, optional premium $2.99 per month subscription)