How can I duplicate a set of tasks for multiple projects without having to type each task over again individually?
This can be done by exporting a project (all tasks from it) as a template and then importing this template anytime you want to add the same set of tasks.
This is a Premium feature and you can see how it works in this video: http://www.youtube.com/watch?v=_Rl_CLGY_3o
Alternatively, (premium feature again), create an email per task you want and add as recipients the projects where you want it to be added.
Canned emails in Gmail or something can speed that process.
I think you might find under votebox "Duplicate task" request to vote for it :)
Here it is - @David, do you know why is it closed?
That has now been changed back.