This is from a post I made earlier
"Flight Simulator X is the culmination of nearly 25 years of the landmark Flight Simulator franchise and the most significant addition to date. Flight Simulator X will be fully optimized for Windows Vista.
Ive been floating about the www looking for anything interesting and found tucked away in a post about gfx cards
DirectX is currently at version 9.0c, and the introduction of Microsoft's Vista operating system will see version 10 and Shader Model 4 making their formal debuts on the PC platform. There's no indication at the moment that DirectX 10 will be released for versions of Windows XP, although it will be available on the Xbox 360, and so the slow feature-starvation of XP users begins, perhaps in the hope that gamers will be tempted to migrate to Vista sooner rather than later.
Now that got me thinking Flight Simulator X will be fully optimized for Windows Vista
Looks like Vista will be essential after all
Interesting info TTT