High DVD is the version for our non-iDrive cars (X3, X5, 3-Series E46, etc). The "Professional DVD" is the version for the iDrive cars. The CD is the version for the older MKIII navigation system, or for single coutries (like I said above, a CD fits a european country or a USA state).
In other words, if you have a X3/X5/etc with a MKIV, there's only one version you'd care - the USA/Europe DVD High.
