Bink posted a link to a very useful article today on a question that needed to be asked and answered: "How much RAM will I need to run Vista?". Bink’s conclusion was in agreement with the original MSDN article. To get a full blown experience from Vista you will need 1.5GB of RAM.
My conclusions? I’m running a home built Intel Duo Core PC with 4GB of RAM with Vista Business x64. When Vista and the usual bit’n’bobs (AV, etc) are running, 1.5Gb is consumed. One thing we’ve all seen from Windows before is the "Field of Dreams" principle: "If you build it, they will come". In Windows, if you insert RAM, it will use it.
I’m not saying your Vista PC needs 2GB of RAM, but I think a basic business machine should have a minimum of 1GB. How this will work in the future, I cannot predict. Most decent vendors will release new verions of products in the coming months to take advantage of the new Vista market. They’ll likely increase their own footprints and therefore memory requirements will increase.
My advice is to start looking at Vista now if being up to date is important to you. Large business are likely going to have application rollouts that rely on Vista features. The security benefits will surely be worthy of consideration. Have a a look at the product, learn it, identify and prepare your deployment mechanism and figure out your hardware requirements. This way, when the CIO says "we need to get this thing rolling" you’ll be able to turn around and say "we’re ready".