Vista will come with 3 GUIs. The one called Aero Glass will need a seperate GFX (not built in) card supporting DX 9c. It will have all those cool transparent window effects. The secong GUI is XP like (non-transparent) but in Vista colors (called Aero Basic i think). The third GUI will be like classic Win 2k style. This means Vista will be capable of running on various hardware. Its just that u'll need a high-end PC for those eye-candy effects.
Also, regarding playing games when GFX card will be busy rendering windows, I've read somewhere that Vista will behave very intelligently in this regard. While you're playing games, Vista will automatically stop/suspend all background processes that are unlikely to be used during that time. It will restart the services once ur gaming session is over. That almost means the maximum possible resources will be available to your game. Now, isn't that cool?
Also, regarding playing games when GFX card will be busy rendering windows, I've read somewhere that Vista will behave very intelligently in this regard. While you're playing games, Vista will automatically stop/suspend all background processes that are unlikely to be used during that time. It will restart the services once ur gaming session is over. That almost means the maximum possible resources will be available to your game. Now, isn't that cool?