wbmw, I certainly agree that SGI is having success with Itanium. They are moving their customer base over to the new architecture. (I am less convinced that they are reaching out to new customers in large numbers. SGI is really small potatos.)
Now, what does that mean? We have two companies who have an Itanium strategy that will succeed - SGI and HPQ. A bunch of other OEMs offer Itanium as check list products but don't take it very seriously for their markets (such as IBM and Fujitsu).
SGI makes low volume, high performance systems. HP is using Itanium in low volume, high performance systems. When we step back to see the forest for the trees then the picture becomes that Itanium will have a chunk of this niche, and is not reaching out to the broader market.
Back when Intel posters were predicting that Itanium would dominate everything, and AMD posters were predicting the demise of Itanium, I was one of the few posters who said that Itanium would have success in HPC because HP would bring their customer base to it, but would not displace x86.
So far I see nothing to contradict my position. Itanium found its niche.