What is the best way to get and set the meta data for mp3, mp4, avi files etc. with .NET?
These are the example class files for different languages found in the MediaInfo.dll zip
You do have to use interop and I don't know if you can edit tags, I've never needed to do that but it's pretty much a swiss army knife at least for getting media information from files.
Link to downloads page (sourceforge)
MediaInfo_0.7.7.4_DLL_Win32.zip