You can pry OpenID from my dead body. It moves user account controls back to the user. Want to delete an account? Delete access to the website rather than, usually, having to email the administrator. Want to only log in once to see what the website looks like? Click "Allow Once" instead of "Allow Forever."
Plus, since you never give a password, you don't have to worry about how they're storing it. Plain text in the database? passwords.txt file in the webroot? Doesn't matter because they don't have it.