The P4 3.06 with any motherboard using the 845PE chipset...or the Granite Bay (E7501) motherboards...but the latter are fairly pricey ($200 USD or more) I would drop some serious cash into some RAM though. On the other hand 2 Xeon's of the speed you want will be cheaper. The killer though is the motherboard will not be cheap and will outweigh the cost of the price difference between the 2 Xeon's and the 3.06 P4. The 2 boards that support a P4 with HyperThreading (which is in the 3.06GHz P4) are the MSI 845PE Max and the Asus P4PE. Both use the 845PE chipset I talked about earlier. You should be able to find either online for $150 or less, especially the MSI one.
