I use TMPGEnc 2.5 to convert my video clips (Divx, Xvid, WMV, etc etc) to a format accepted for DVD video (MPEG or MPEG2). Then once my clips are converted I use TMPGEnc DVD Author to create my custom menu's insert the clips and produce the file structure needed for a DVD (AUDIO_TS, VIDEO_TS, IFO, BUP etc etc).
This program also has a burning tool built in which I use to burn all my DVD movies I create. As Warez mentioned though Nero does this as well. I use DVD Shrink when I need to backup any of my scratched DVD's it works great.
I also played with this program called Super DVD Creator 8.5 which allowed me to directly insert non-DVD supported formats (divx, xvid, wmv etc) into the creation software and burn the disc, but I didnt have the cool menu creation options as the above program.
That is correct. Thats the only reason I listed all those other pieces of software and steps. If it is simply to backup a DVD then I agree DVD Shrink is unbeatable sometimes it needs help from DVD Decryptor (Damn you SONY!!!!), but usually it goes good. If you need to convert clips though if various formats (WMV, DIVX etc) you will need assistance from conversion tools such as I listed, but there are tons of others as well. Just have to try various ones and see which one you like best.