It also happens to me very frequently on Mac OS 10.6.8. It is necessary to set default graphic renderer to OpenGL (it helped me alot)
that can be done in startup file, and also check you OpenGL bugs and if there is any try workarounds, I have to use this workaround:
Although most of crashs are resolved by using OpenGL, there are many other unknown cases. I appreciate if someone can help for arbitrary crashs.