Gamespot has a pretty informative interview with one of Microsoft’s XNA strategists (Dean Lester, the Windows Gaming general manager, in fact), and while there’s lots of goobledegook about giving “Level” ratings to PCs to determine what sort of games they are capable of playing (“I had a Level 5 machine, but the new video card puts me firmly in 6.4 territory, although since I traded in my aluminum case for one with better armor class, my encumbrance drops my THAC0 to…”) there’s also some juicy bits about the Xbox 2 in there, as well, including work that Microsoft plans for all Xbox 2 peripherals to work on PCs, as well. Either than means all PCs are getting an Xbox add-in card, or we’re pretty looking at something like USB (the existing Xbox controllers are essentially USB already, in fact).
This had already been happening to some extent on consoles already. Many USB peripherals like steering wheels work fine on a PC or Playstation 2 (which has proper USB ports), but it will be nice if this is embraced by the manufacturers instead of given an occasional nod.