If you enjoy using Basecamp just as much as I do, you’ll probably enjoy it even more, when you learn that it is possible to use short-cut keys. You just hover over a todo-item and click ‘e’. Then you’ll edit the todo item. After you’re done, you just hit return and the item is saved.
A small tip I learned from the 37Signals product blog: http://productblog.37signals.com/