Ubuntu died on me tonight, after installing the "tested" version of the nvidia driver that Ubuntu supplies. Kernel panic before it even mount the / fs. I was able to boot into recovery and uninstall the new kernel and nvidia driver, and saved the system. But it's quite unacceptable, I must say. I've had stuff like that when I used to run Linux more than 10-20 years ago, but I thought we were past that now. I never had any modern Windows or OSX unable to boot.