To-do app for Mac OS X

Solution 1:

You have the great wunderlist which is free, provides collaboration and a companion iPhone app (also free). Does what it's made for. Customizable and sexy :)
(No I don't work at 6wunderkinder!)

Solution 2:

Things (39$) is best to-do application i've ever used. It's a simple application with powerful features.

My favorite feature is synchronizing between mac/ipad/iphone. One disadvantage that it is paid application.

Solution 3:

iCal that ships with OS X has a ToDo List feature that works well.

You'll need to be more specific about which features of MyTinyToDo you like, if you are wanting better recommendations.

Solution 4:

I use ToodleDo for all of my To Do lists. It's a website so it is accessible anywhere (I use it as the default page in my browser on my laptop) and they have a native iPhone app that does a great job syncing. It's not Mac-native, but it is very agreeable to Mac users and you can export your lists as iCal calendars if you so choose. You get a lot of functionality for being free, but it does pay to subscribe if you have long-term uses for it.