A Windows Vista-capable PC includes at least:
* A modern processor (at least 800MHz)
* 512MB of system memory
* A graphics processor that is DirectX 9 capable.
A Windows Vista Premium-ready PC includes at least:
* 1GHz 32-bit (x86) or 64-bit (x64) processor
* 1GB of system memory
* A graphics processor that runs Windows Aero
* 128MB of graphics memory
* 40GB of hard drive capacity with 15GB free space
* A DVD-ROM drive
* Audio output capability
* Internet access capability.
Not too steep for the basic version. Pretty much any new desktop or laptop for sale right now has the guts to handle Vista lite. Premium is a different story. If you go to Microsoft's page, you'll notice footnotes after the Premium version processor and GPU requirements. According to the outline on that page, to run Aero on a single display at 1,280x1,024 (the native resolution of most LCDs), you'll need at least 128MB of dedicated graphics memory. If you need 1GB of memory for the Premium Vista, that rules out any of the current-gen Intel or other integrated chips. You can also forget about most of the lower-end HyperMemory/TurboCache 3D cards from Nvidia and ATI, because those chips share all or part of the system memory for graphics, taking away from the overall system memory total.
Now that the hardware requirements are public, you can shop smarter. Just know that you need to dig a little deeper into both the system and the graphics memory in order to get Vista to look its best.