While I agree that for the most part if given the opportunity to manipulate the shooting scenario, you could basically get a close to or similar look to the 135 with the 100 and/or the 70-200. However, it doesn't change the fact that for reasons which I can't quite explain in a scientific fashion, I can consistently get shots that look a certain way when the 135 is mounted while I'm running and gunning (without having to pay mind to subject to background distance and shooting distance from subject etc).
I have the 85II, 90tse, 100, 135, and the 70-200II. The 100 and the zoom get the least amount of usage. The ONLY time I pull the zoom out is for paid shoots when I need the zoom flexibility and the 100 is strictly a macro lens (for my shooting needs). Even then, the 100 is only pulled out when I need 1:1 macro which is not often. Most of the time, the 90tse is preferred for close up product type shots.
This is not to say that it will be the same for you. As others have stated, your question is one that cannot be accurately answered by anyone else other than yourself as you are the only one that truly knows what your needs and preferences are.
+1, a well reasoned response John.