HP's flawed masterpiece is a punchline. It deserves better.
I used Itanium starting when I was eighteen years old, across HP-UX, Linux, NT, and VMS (but never Nonstop.) I always enjoyed the platform - it had an amazing OS selection and was an assembly programmer's dream. The handling by HP and Intel of Itanium's demise was (and is) painful, but it was an architectural dead end.
RIP.
Everything you know about Itanium is wrong.
The very incomplete annotated list of Cancelled Itanium Things.
History of Itanium vendors, including some lesser-known ones.
The "Itanium Survives" alternate timeline nobody asked for.