To look at the different features, click on 'List.' There are other Acrobat products with varying degrees of features. Some people might think that Acrobat 8 Professional is only necessary in a business environment, but if you are doing any work with sending documents, editing, commenting, etc. A lot has been added to Acrobat 8 making it much easier to use and a much fuller package. He has Acrobat 7 Professional, and I find myself telling him to look for this or that only to find that it is not in Acrobat 7.
Since I have been working with a friend of mine who is putting out a newspaper, I have used Acrobat 8 Professional a lot recently.
Of all the programs in the Adobe CS3 software packages, Acrobat 8 Professional is the one that is the easiest to use if you want to just use it in its bare bones form, ie., standard PDF creation.