Don't get your hopes too far up about the uber-sexy HP rigs just yet... they will run exceedingly poorly with x86 code. Wait and see who's porting stuff when before you jump on them. If the software you want to run is Itanium2 native, however, then the Itanium2 will be quite a screamer, as the rest of the performance measurements indicate. I would price out the Dell Xeon rig and the Boxx Opteron rig. If you compare a 3.06 GHz XeonDP with 1 MB cache (well, a dual I mean) to an (also dual) Opteron 2 GHz machine, you should be able to get comparable performance from either rig, and there is a possibility for better performance from the Opteron if PGI's AMD64 compiler optimizes well for Opteron native code. There are too many ifs and maybes involved to provide a good recommandation right now, because there are too many variables, and two of the three platforms (Itanium2 and Opteron) are too new to be sure about. Both will sink or swim based on software support...