I confindently backed up my very nice Vista intallation with Acronis True Image 10, only to find that the "Documents and Settings" Folder was empty. I suspect that if I'd done the image from the DOS recover CD, it would have been OK, but I did it from Vista and I suppose the Directoy was locked. I did a restore and lost my beautiful and well tweaked Vista installation.
On other matters TrendMicro PC-cillin 15.3 Internet Security works with Vista. You get AV, Firewall and other features. Great software and more configurable that MS Live OneCare.