I need a good program for converting VOB files to AVI files

i need a program that wont mess up the sound

If those .VOB files are on your computer, this video converter can convert them to .AVI.

If they are on DVD disc, you need this DVD Ripper software.

WMV Video Converter for mac, DVD to WMV Ripper.

Hey, pal. If you are using a Mac, I think iSkysoft iMedia Converter for Mac would be the best choice, which can convert DVD and Video both to iPod (also to Quicktime, iMovie, iPhone...).
It was recommended by lots of famous mac-related sites, such as macworld.com, macnn.com, maclife.com, etc. You will never know how powerful it is. It’s the best all-in-one Mac converter I have used ever.
Glad to share.
And you can find the truth on iSkysoft official website:

http://www.iskysoft.com/imedia-converter-mac.html?page=126

Multimedia Editing and Converting App: Video Converter, DVD Ripper and iMedia Converter for Mac.

i am using iskysoft video converter(for windows).
so far so good.