Although Vista and Win7 both have better-than-nothing backup programs (at least, in some editions), you need to find the right solution for your data. And, you need to test restoring from a backup before you have an emergency. I’ve started using Reflect. I haven’t used it enough to find its flaws, but two key features for any backup program: automatic scheduling (daily is best) and access to files via Windows Explorer (lacking in Vista’s tools).
Additionally, the app uses the Windows Volume Shadow Copy Service to take disk images while Windows is running, so you don’t have to let your system sit idle while Reflect does its work, or boot to external media just to create a disk image. Additionally, after your disk image is generated, you can browse it using Windows Explorer, so you don’t have to fire up an additional app just to pull a file out of an old backup.