I've been holding off writing this, since I've had nothing but instability with C7.x since day 1. However, last week I started with a clean project in the 64-bit version and so far have not had 1 crash.
I've always been reluctant to try 64-bit, since I rely on too many 32-bit plug-ins (SoundToys, etc.), but I have been able to set these up inside Vienna Ensemble and run them back into Cubase. And it is working brilliantly!
So, I will probably never know why the 32-bit version was so troublesome for me. I would get random crashes daily, which made it impossible to use. I had tried everything under the sun to resolve its issues, including not using any 3rd party plug-ins, and it would still crash.
So, I'm happy at last!