Screen protector or case?

I'm getting the galaxy nexus in october and I was wondering if I should save up 4 a protector or case.

One day me and my mom were at a swimming pool and she had a screen protector and dropped her phone screen first on concrete and it's still good as new. But my friend had a case 4 her iPhone and her screen was cracked. You know she was mad and I don't want 2 go through the anger.