A lot of people would say that Scenarist is the best, but I haven't used it myself. I've used DVDit Professional from Sonic and hated it. ReelDVD (yet again from Sonic) is tolerable, though it's got a lot of quirks to get used to. I went ahead and installed Adobe Encore since it came with the current video suite, but I haven't tried it yet. I have to create a few DVDs in the next couple of weeks, so whether I try Encore out or not may depend on how frustrated I get with ReelDVD.