Microsoft Windows Vista is finally a good choice for operating system. After service pack 1 was released, my recommendation is to use Vista instead of Windows XP. Vista provides much higher security that XP.
Regarding backup is this new operating system almost identical to its predecessor. Microsoft backup is still a good choice if you have s spare hard drive or similar to use, but I suggest you read this post before choosing your solution. Vista backup is great but also dangerous if you are not storing your backup securely. I would say to take a good look at other options because the risk is simply too high and storing your data securely is what its all about. Keep your backup as far away from the originals as possible and invest a few bucks on a good solution.