I think I might grab a nice discounted price Northwood for the next couple of months and move to Athlon64 / Prescott once BTX, PCI - Ex, and DDRII go mainstream. Although Prescott's performance at these relatively low speeds is a little disappointing, if Intel can clock these suckers up as fast as the 55% increase in pipeline length would indicate they should, I think they'll be very nice.
BTW, if these chips can overcloock well, I don't see why an overclocker would choose Northwood over it; performance is similar at equivalent clock frequenc. So if 2.8E@ 4.0 GHz on air is feasible, it will outrun nearly all Northwood overclocks.