I've written several articles on todo list.
Now, I'll mention filtered solutions. You can choose one from below as per your requirements.
Basically What is a todo list do?
It's a simple list of tasks to do. If we going further, we need to remember some task on particular time. So, we required a reminder. Another one is we need to get reminder a particular task on every year (Birthdays, Anniversaries etc.). So we need recurring task option.
Another one is it should work on android, IOS, Desktop etc.
I'll list out some major solutions that I tested. I know that there are so many other fantastic solutions.
Google calendar: (Web, Android, IOS, offline in chrome) It has all features. Tasks, reminders, recurring reminders, SMS alert, email notification...
Workflowy: (Desktop offline(Chrome), Andoid, IOS, Web) This is my primary todo list. Its just a list. No reminder, no recurring tasks.
ToDo list: http://abstractspoon.pbwiki.com/FrontPage (It's a desktop/ portable app) it's a tons of features like, calendar, gantt chart etc. Easy to use.
ToDo text: http://benrhughes.com/todotxt.net (Desktop app) It's main attraction is it saves data as plain text. It has very simple hotkeys too.
ZimWiki: To do plugin. It's also saves data as plain text.
Other mentions are using pen and paper by super focus method, outlook todo, onenote todo, gmail inbox todo, google keep reminders, wunderlist, remember my milk etc.