I don't think it's just for girls --
My almost-5yo twin boys LOVE High School Musical! They're always running around saying, "What team? WILDCATS! What team? WILDCATS!" "Keep your head in the game!"
And I always have that one song from the cafeteria in my head "Oh no no no no, no no no, stick with what you know! If you wanna be cool, follow one single rule..."
I think it's adorable.
Now, HSM2 is definitely a little more mature, and I don't let them watch that.