Well, I just checked on this Zac Efron guy and I don't understand why everyone is making a huge fuss about.
1. He does have some acting experience, even if most of his acting consists in Disney's shows and small roles in TV series.
2. Nobody else comes in my mind when it comes to similar looks with Light, and he really looks like Light.
3. Even if some other 'super' actor is chosen for Lights role and that would satisfy everyone, lets not forget that there are other problems that consist, like who's going to play L, who's the director, and how loose the American version will be.
It's really to early to jump into conclusions, so please people, stop all this OMG! Zac Efron as Light??? WTF!!! nonsense, it's bad for your health.