I work mostly with mpeg2 captures, so my interests have been fairly narrow in scope, and I am purely amateur. I have worked with avi captures in the past and still do a bit of conversion work on clips found online.
I use VideoReDo Plus for editing mpeg2, though I don’t do anything elaborate. Most of my editing consists of cutting out commercials or trimming ends. I picked this program because of its ability to cut mpeg2 with minimal reencoding of the video. It also has a very handy tool for video/audio sync problems called Quickstream Fix.
My main authoring program is DVDLab Pro. This is one of the more expensive programs in my software collection, and I debated a long time before getting it. It has a flexibility and ease of use that I didn’t find in the free authoring programs and can produce very detailed, elaborate menus on those rare occasions when I want to get fancy. 
It also has the ability to import complete dvd video when I want to rebuild a dvd, so I don’t have to demux to elementary streams beforehand.
I have tried several other programs, mostly through their trials, including TMPGenc Author, Womble Mpeg Video Wizard DVD, GUIforDVDAuthor, DVDStyler, Sony Vegas, Avid Free DV, etc. Many were more oriented towards camcorder users, and thus didn’t fit my needs very well. The free authoring programs were either too clumsy or too simple for me.
