This is a very interesting article about wealth taxes. Did you know that Donald Trump has proposed a net-worth tax? That really makes me think much more of the guy.
I think I like the concept of the net-worth tax more than a generalized wealth or asset tax. Specifically, I definitely think we should subtract the value of secured debts from the assets against which they are secured. Perhaps we also should deduct the value of other special classes of debt (e.g. education loans) from the total. I don't generally like encouraging heavy use of unsecured consumer debt. And I certainly wouldn't want to allow the subtraction of the kind of "loans" that are frequently made by corporations to their CEOs (and then later forgiven, effectively giving the CEO a bonus without mentioning it in the official statement of executive compensation).