I agree that different tasks require different approaches, but I'd be wary of jumping from low fidelity straight into Photoshop. I've done this in the past, but it doesn't work well for quick iterations. No matter how many people say it works fine on paper, you will always find that changes need to be made as you go along the fidelity journey. Also, with Photoshop, you can't really show interactions well.
What happens when I click this button?
What happens when I log in as an admin user, put to a regular user?
I generally go:
Pencil & Paper -> Paper prototypes -> Balsamiq -> Visual design (either in browser using a pattern lab, or Photoshop) or
Pencil & Paper -> Paper prototypes -> Axure -> Visual design or
Pencil & Paper -> Paper prototypes -> HTML
It depends on the complexity of the project, but unless it is a minor tweak or small addition, then I find that it is way more time consuming for the developer to be able to see something working, rather than something static.