DX10 may yet be utilised on XP machines, for those who havent read anything about this I suggest you read up.
As for the hardware limitations and FSAA + HDR - I dont want to get into the techno complexities of why they both dont work together on older graphics cards.
Suffice to say, VISTA and modern graphics cards drive the market, some of you guyz that hope every latest game will run just fine and dandy on your 486's DO NOT DRIVE the industry........... expect a DX10- patch for sure...why ????
Because its the future