Q: What is the best way to make an animation of glass breaking?

A: If it is flat glass, you can turn Show all lines ON and divide all edges of the faces to get the irregular shapes of the broken glass parts. Or you can use Tesselate, but it looks too regular - you will have to move some vetices around to get a better feeling. You can use an AXP to explode the parts, or you can Explode the faces / detach selected faces and animate every single part.

Lofted objects have more faces and an AXP (as found on Yost Disk #2) should do the work fast and easy.