[arez]

Person.PersonID stutters, you already know that you query on the person table you don't have to repeat it again. Naming it ID is the same consistency

[default-kramer]

I like "Person.PersonID" because then "alias.PersonID" will produce an error if "alias" does not have a "PersonID" column. If every table has an "ID" column then "alias.ID" pretty much never fails, even if you typed the wrong alias - you just end up joining on the wrong thing and getting the wrong result set.