I wish this discussion had received this much attention a few months ago.
In retrospect, the solution I came up with and implemented is insufficent. With external authentication, we now have 3 main possibilities for what name the user should go by: Real Name(with all it's variations), Username, and screen name.
I think all of these variations should be user-configurable. If a user really does want to be know by his real name, instead of his screen-name, let him do it. Likewise, if his username is already generic and anonymous enough, why require a seperate screen name?
My previous work put all of these decisions in the hands of the administrator, I think they should be up to the user with the administrator setting the defaults.
Thoughts?