What are people's opinions vis-a-vis my choice of authorization plugins?

I'm slowly but surely putting together my first rails app (first web-app of any kind in fact - I'm not really a programmer) and it's time to set up a user registration/login system. The nature of my app is such that each user will be completely separated from each other user (except for admin roles). When users log in they will have their own unique index page looking at only their data which they and no-one else can ever see or edit. However, I may later want to add a role for a user to be able to view and edit several other user's data (e.g. a group of users may want to allow their secretary to access and edit their data but their secretary would not need any data of their own).

My plan is to use authlogic to create the login system and declarative authorization to control permissions but before I embark on this fairly major and crucial task I thought I would canvas a few opinions as to whether this combo was appropriate for the tasks I envisage or whether there would be a better/simpler/faster/cheaper/awesomer option.

What about cancan by Ryan Bates? Here you can get a complete visual guided implementation

Take a look at this, it might help:

Basic Rails 3 engine utilizing Authlogic, CanCan and Easy Roles

What about Devise? Take a look at the railscasts.com site.