Bastien piano basics is a great series of books that takes the young learner right from the beginning to an intermediate stage. I can't recommend them enough with really fun tunes that resemble other more popular tunes.
The pictures are great and it gets started on left hand chords early on which is good, there are also some really nice duet parts for the teacher to play along with the student.
She likes the music ones the best though, the Bastien Piano Basics also do theory books but I'm sure that would be with most. Theory never is as fun as playing songs.
