I remember seeing some benchmarking....
...between a "nocona" core Xeon and a comparably priced Athlon64. A (more expensive) Mac G5 processor was in there also and basicly tied with the Athlon 64.... It's been a while, sorry.
Besides, Intel has now adopted the AMD standard for 64 bit, EM64T. IA-64 is now only used in Itanium chips which may be phased out soon, and are outside your pricerange.
