I use Toodledo for long term things. Toodledo has the most flexibility for complex tasks. They also are a very customer-friendly shop so I like to support them,

I use Toodledo for long term things. Toodledo has the most flexibility for complex tasks. They also are a very customer-friendly shop so I like to support them, but their iPhone interface is not great for quickies. I use them for stuff I would use a computer for anyway, and tasks that I want a history of, even after I have done them. I use a shortcut to google tasks for the equivalent of post-it-notes, i.e. stuff I want to flush out of my brain and do in the next few hours. Nothing that would carry over for more than a day, and stuff that once done, I delete.