Hi Michael (great name) – I have started thinking about how to use Evernote for my genealogy research as well. For me, tags are the way to draw a common thread across notebooks as well as across many notes, so that’s how I’m approaching it:
– First, I’m going to make a notebook for each of my separate research projects. That way, while I’m working on the project, all of the notes I need are close together.
– Then I’m going to tag things with Surnames (I’m not sure about creating a tag for each individual person), so I can find Surname information across projects
– I’m also going to create tags for Places, with a separate tag for State, County and City (99% of my stuff is US-based; I’ll probably add Country tags once I go across the pond)
– Then, when the project is finished (ha! like a genealogy project is ever finished! :), I will create a unique tag for that Project and collapse all of the notes back into my may genealogy notebook

Like you, I’ve struggled with the knee-jerk reaction for having a hierarchy…but I’m getting more comfortable with the power of tags and their ability to help me pull information together in ways that would normally break a rigid hierarchy.

That’s what I’m thinking…at least for now. Looks like you wrote your comment several months ago…how has your genealogy tagging strategy shaken out?