Could someone please formulate why we need a project list? Not to forget multi-step tasks?
Exactly. I have very few projects with only a single step. For those that do, I usually put them in a more generic project group ("Personal" or "House" or something) so that I don't need to create a new project for a single item.
It also helps keep things simple. For example, I can list a task as simply "install wordpress". If that was by itself, it'd be useless -- install it WHERE? However, as part of a larger project, I can see that it's under the "XYZ Site" project, so I know where to install it.
As David Allen points out, the purpose of the projects list is two-fold:
(1) It is the one place you put a stake in the ground that shows your commitment to some multi-step outcome. This is the list that governs most of what you do every day. It is the list of things you are working toward by completing your actions.
(2) It serves as an "index" for your next actions. As you capture tasks under each of your projects, the next, kick-start action serves as a "bookmark" for where you are in completing that project. Of course, you need not only have one action from each of your projects on your action lists, but you should have *at least* one.