Why not upgrade to Vista?
Bottom line is don’t upgrade from XP to Vista too fast if you are not sure about your current hardware compatibility. Unfortunately there are not only minimum requirements for Vista but incompatibility issues with older applications. Best thing to do is either stick with what you know works (your current Windows XP system for example) for now. Otherwise if you are getting a new PC already preloaded with Vista or are keen on installing Vista yourself on a new hardware platform the best tip I can give you here is to ensure that ALL your hardware is supported buy the manufacturer with windows vista drivers. If there is no indication that your hardware manufacturers are further updating the drivers to support the new OS then stay away otherwise you will be in for a few headaches.
Common issues as a result of not doing a due diligence investigation on your hardware support or Vista or vice versa, is that you will have to settle for using an alternative similar driver or a generic driver which will undermine your hardwares full potential aswell (not to mention popup messages that indicate driver issues, errors or even the all familiar blue screen of death).
Here is Microsofts Hardware compatibility list however I strongly recommend you check directly on the hardware manufacturers driver download section for the latest vista supported driver. Also found on winmatrix.com a list of compatible/Incompatible hardware devices.
Minimum system requirements to install Windows Vista
It depends. To run Windows Vista Home Basic, the minimums are an 800-MHz or faster processor, 512MB of memory, graphics hardware capable of SVGA (800 by 600) resolution, a 20GB hard disk with at least 15GB of free space, and a DVD drive. If you want Vista’s Aero interface (and you do for looks), you’ll need a graphics card that can handle DirectX 9 graphics APIs with Pixel Shader 2.0 3D texturing, has a Windows Vista Display Driver Model (WDDM) driver and at least 128MB of graphics memory, and supports 32 bits per pixel. See my article on Vista certified video cards for examples.
One last thing, its never good to be the fist to upgrade to a new OS, best you wait for the first of many service packs to be released for Windows Vista before you jump into the water.