I think that the PCs of late 2006 will by-default ship with a "bare minimum" of 512 MB DDR2RAM running at high frequencies, the processors will essentially and likely be dual cores or ne other upcoming processor technology running at more than 4 gigs .. even HDDs will be 160 GB for the entry level with Dx9.0c Gfx cards becoming so hot even now!!!! With such "monstrous" config., I think ppl will need the software framework to utilize their complete potential (I mean the processor speeds, newer instruction sets for better computing capabilities, and data crunching capability) .
That is xactly why ppl will go 4 futuristic operating systems like VISTA which will definitely be optimised to run on futuristic systems, where XP may have some compatibility problems as Win 98/ME has now with some latest hardwares and softwares.