Username or EmailPassword
Another variant is the one oulined in this paper 
"The design includes two interfaces between which the user can easily toggle: (1) an interface personalized by the user containing desired features only, and (2) the default interface with all the standard features."
Instead of fixed interface "levels" you have the "personalized" level and the "kitchen sink" level. With an easy way to toggle features from the latter to show in the first.