ConvertXtoDVD is a commercial product that is recommended around here quite a lot. Not free of course. Its predecessor was DivxtoDVD, and you can still get the last free version of it here: http://www.aplusfreeware.com/categories/Audio-Video/vsoDivxToDVD.html
SUPER is a free video conversion tool. Found here: http://www.erightsoft.com/SUPER.html
I wouldn't characterize any of these as the "best", but they usually work well enough. There are other easy to use choices, like the programs from Ulead, Nero and Pegasys.
I personally use a separate mpeg2 encoder, then an authoring program. And I never get the video/audio sync problems that seem so common in the one-step programs. If you wish to go this route, look at TMPGenc Plus 2.5, which is a reasonably priced mpeg2 encoder and an authoring program like TMPGenc Author 1.6 (if you can still find it for sale) or a free one like DVDStyler or GuiforDVDAuthor.