What to do with a HP Itanium box?
Debian 6.0 aka wheezy still supports ia64. If you're comfortable with Ubuntu, you'll find Debian quite familiar. With some apt repository tweaking, you'll be able to get similar package versions as well.
VMware never supported Itanium. They only support x86 and x64.
Windows Server 2008 R2 is supported on Itanium. That's the current version of Windows and it will be supported for a good few years (10 at least, I think).
Several Linux distributions support Itanium. I don't think Ubuntu is a common distribution for servers and there would thus be little demand for an Itanium Ubuntu. Ubuntu's parent distribution, Debian GNU/Linux, runs on itanium.
CentOS appears to be a Red Hat derivative. Better look at major distributions for Itanium (server) hardware.