Should the OS be on a separate partition than everything else?

I am on the SEPARATE camp. It allows me to Image Backup C:. At signs of trouble, I can restore to my last Known-to-be-Good restore point and am back in business in 15 minutes, without spending time troubleshooting why and running a virus scan or any of that time consuming stuff, without disturbing the data which is in another partition. Sure this can be done without a separate partition but it's so much easier and quicker.

Will let the folks on the other camp have their say.