You know, there really is no such thing as an "absolute winner" in this field... It´s not so easy, because it depends on your particular needs. I´d say the best overall choice would be (and that includes AMD Athlon XPs, Dual MPs, Dual Xeons) the following:
Intel Pentium 4 3.06Ghz, 533Mhz FSB with Hyperthreading technology
Asus P4T533-C i850E-based motherboard
2x256MB Dual-Channel RDRAM PC-1066
That´s what I would qualify as the current top model, overall, in terms of performance, stability and compatibility. Some might choose a Granite Bay configuration over RDRAM, or even SiS655, but the i850E is still the best performer. A Granite Bay/SiS655 would cost you less and would be the second choice. The Intel chipsets <i>should</i> offer you all stability you´ll ever need, and there are no compatibility issues that should concern you. Not with the Intel chipsets, they´re well designed. That might not be the case with SiS655, though... So I´d recommend the 3Ghz P4 and an Intel chipset, either 7205 (GB) or i850E.