We've begun the process of hi-fi wireframing a new site for an awesome client. These are all based on lo-fi wires that contain the written strategy.
I think I tend to add a little more fidelity to this stage because it's nice to get buy in on things like general layout and type hierarchy. It also helps plan what visuals will be needed and better plan for the visual design stage.
Have you ever done this approach and do you find it useful? Or do you find it restricting once you get into visual design?