I thought five editions of Windows Vista was a bit much, but then I saw that there are eight editions of Office 2007. Take a look at the comparison matrix from Microsoft’s web site:

There are holes where you wouldn’t expect*, and there is no single edition that contains every Office program. Office Ultimate lacks one program — how is that “ultimate”? I understand the theory of market segmentation, but there’s also the reality of human confusion.

* In one way, it’s not quite as strange as it first appears — for example, Office Professional doesn’t come with Outlook, but it does come with Outlook with Business Contact Manager. But still…