what is the absolute most pro grade dvd mastering authoring software i can buy?

Tom, the industry standard is Scenarist but the learning curve is huge and your talking big bucks.

The rest depend on if you are on PC or Mac. Mac would be DVD Studio Pro and PC has a few, I use Adobe Encore which is great if you have used Adobe software.

ok michael i am completing a project in vegas it is hdv and i want software where i can get pro results...let me check out encore if it's for pro stuff

One word of advice on Encore, I have been using Encore since its original release and that means working through many initial bugs. I have always found the Encore works best when you encode your video to MPG2 before you get into Encore. It seems all the problems that come from users have one thing in common, they use Encore to do all of the encoding.

Maybe the bug is fixed, maybe not, I still use third party software to encode.