Is there reasonable doubt that Travyon Martin is dead? No.
Is there reasonable doubt that George Zimmerman killed Trayvon Martin? No.
Is there reasonable doubt that the killing was justified and/or committed in self defense? Yes.
Conclusion: no 2nd degree murder conviction
However, I could see a manslaughter conviction, since the evidence shows that Zimmerman did seem to display a disregard for human life, and acted in an irresponsible manner.