I usually avoid sweeping statements for exactly that reason but I think it's true in this case. If anyone has a good counter argument I'd be happy to admit I am wrong. Just to give you some idea where I am coming from I used Ubuntu on my work laptop for about 5 years. I got a new machine recently with Windows 7 and I just couldn't think of any good reason to install Ubuntu.
I can think of a few good reasons, but hey are purely developer-oriented. At my last job, I had an Ubuntu-based desktop because it made virtualization cleaner with a more stable base system—and the company wouldn't buy Macs. Windows ran in a virtual machine, and I developed on Linux, Windows, and a couple of Unixes. For that job, Ubuntu was the best choice I made.
Problem with making sweeping statements like this is that you now make it difficult to continue any sort of rational discussion.
(and so, I downvoted you for that last line even though you had some good points to make)