Well let's assume a certain specification of hardware shall we? We don't need to support every PC out there, just a subset. This can be done by specifying supported hardware up front, and deviances aren't guaranteed to work.
In this case, how about targeting AMD's forthcoming Llano processor and surrounding platform?
i.e., 2, 3 or 4 x86-64 cores, 160,320 or 400 AMD/ATI Radeon 6xxx series shaders, UVD3 (video decode), AMD/ATI SB9xx southbridge features (USB3, USB2, SATA3, ...).
No, and I will stop you right there. Isolating sections of the x86 'standard' people own would be like making a fuel that only runs in 2% of cars on the road. Your example would not cater for 8/9 of my machines....all of which play 1080p video files so not exactly ancient.
This is why Windows needs about 1gb of drivers on DVDs, and that humongous registry file.