That really depends on what you intend to do, but for Professionals I´m convinced Sonic Scenarist is the best tool available.
I agree with PedroMR. It really depends on what you want to do with it. For consumer level tools I consider TMPGEnc DVD Author to be excellent for very simple discs and DVD-Lab to be hands down the best for everything else. However, if I just need to make a movie only disc I often use the authoring feature in Rejig. _X_X_X_X_X_[small]Looks like I picked the wrong week to stop sniffing glue DVD Rebuilder Guides: http://www.afterdawn.com/guides/archive/dvd_rebuilder_tutorial.cfm http://www.afterdawn.com/guides/archive/dvd_rebuilder_tutorial_advanced.cfm[/small]