3D view reset

 From:  SteveMacc (STEVEH)
Is there any way of resetting the 3D view so that z is up and the horizon is reset to horizontal?

I have some models that were saved when the view option was set to "free rotation". They were saved with the z axis tilted. When I open them with the view option set to "rotate around the world z-axis", they are still tilted and I don't see anyway to straighten them.