I developed Centask to address the chaos you are describing including Gmail. The idea is to organize and schedule Gmails, todos, links, ideas, etc. in one master outline/todo list. The tools you are describing are online tool so each of their tasks has a unique link which you can add to Centask with a click on a bookmarklet which adds it to Centask Inbox. you can then schedule it, add subtask to it, drag it as a subtask to other tasks, add notes to it etc. The key is that all items including links and gmail are treated equal and have exactly the same set of features