many years ago I had an NT 4 Adminstration Manual written by Mark Minasi. In one part, he was talking about how you will need to create swap files on your hard disk because you couldn't buy enough memory. He joked "Where are those 1 GB chips?"
Well, they are here. And the second joke is that in order to run Vista you will need two of them. Obviously the start of the next cycle where IT managers are persuaded to throw out every single machine the company owns to install the new operating system.
Sadly, there are a lot of middle managers in IT who love this stuff - crack open the pork barrel, lots more money coming in for hardware and software upgrades, and our staffs will be busy for the next year too. This really does nothing except further turn IT into a janitorial function; what they really should be doing is being the spearpoint for other technologies such as solar, wind, alternative energies, because they are the group that is most equipped to embark on these endeavors. Upgrading to Vista? The joke is almost certainly on you.