Well I must say that I myself get lost in it sometimes as well. You see, AVID has got many, many programs developed by them, or they bought it on their behalf, but well, still a fair few of programs remain in their store. They've got some Audio tools right now, and most of them is video editing. You've got a number of video editing, but most of them are designed only to suit one's need.
AVID DV for example is especially programmed for DV input. As for me, I've got Avid Xpress Pro, which in my eyes pretty much consists of everything. You've got Avid Xpress and Pro, then there's HD (for High-Definition), AVID Symphony for very big projects (used for real films, if you have the SEE of LOTR:ROTK, you will see that they as well edit on Symphony). I've seen a program for broadcasting, they even produce hardware to speed the video editing up, etc.
So you see, AVID is a big company and produces many many products, each of them having their own backgroudn or territory.
You really have to take a closer loo yourself on
www.avid.com if you are to discover every program's capibilities.
Good luck,
gotan