One of the exciting new features of Vista is the new "glass" interface, called AERO.
But if you are considering upgrading to Vista note that if you do not have the right sort of graphics card you will NOT get the AERO interface, you will get basically the same interface you get in XP.
Many cheaper computers come with "on board" graphics (built into the motherboard) or a basic graphics card.
These WILL NOT give you the AERO interface.
If you want the AERO interface you will have to get a NEW a graphics card.
Most graphic card suppliers are listing which cards support AERO.
For example ATI Radeon have produced this list of their cards that support Vista:
http://ati.amd.com/technology/WindowsVista/Pro ducts.html
And nVidia have produced this list of their cards that support Vista.
http://www.nvidia.com/page/technology_vista_ho me.html
So simply put, if you have a basic PC or laptop. with basic graphics support, you are very unlikely to get the AERO interface.
I know it all seems very complicated but I am afraid that is the price you pay for upgrading to Vista.
Personally I think Microsoft have produced a Rolls Royce (and not a very good one at that) when many PC users want a Ford Focus