I think what you are seeing is not the 'required' Vista footprint but the amount of memory that Vista is using to give you 'smooth', optimal performance.
I have a 4G system and with NOTHING running, task manager shows that I only have 76M free. I am sure it is using all available memory for pre-fetching; that memory which is just sitting around, not doing anything productive...
Whenever I load one of my normal working programs, it loads immediately and memory never appears to be running low. The opening screens of my standard apps just pop up. My programs start much faster than I have ever seen in XP.
Thanks again for the reply. The install took a bit to do, but so far I am VERY happy with Vista. I saw the 720mb under the Task Manager and was just confused as to what that meant. I think the most I ever saw in XP was 250mb or something. Either way I'm fine...more curious than anything.
Aero and the new Side Bar look great IMO and is very smooth. I've moved from a socket 939 and XP to an e6600 and can really see a difference in the OS.