|It's unclear at this point if additional memory will be required to run games in Vista over XP. |
While Vista itself needs more RAM for basic OS operations due to the architecture of the GUI among other things, gaming possibly may not suffer from this and require more RAM. The reason is the GUI in Vista will be DirectX, not GDI. So while in XP, GDI and Direct3D are both running while gaming, with Vista, only DirectX will be running. (Critics who are gamers however do point out this potential advantage for DirectX games won't be there for OpenGL.) Also, the network stack is completely rewritten to be more efficient.
Any benchmarks right now really don't prove what performance numbers will be like yet since Vista is still not gold.
According to Technet events I've attended, Microsoft reps are saying 1GB is a realistic minimum, but 1.5-2GB would be optimal. More than 2GB would be unnecessary and probably not beneficial for most users, gamers included at least at the time of Vista's release. Obviously, as the patches keep mounting after that, more RAM may be needed later.
"How many squirrels had to die to make you look fly?!"