I just deployed SP1 on my laptop with Vista Business installed. I ran into an interesting occurrance. As my first action despite the prompt that Service Pack 1 was successfully installed, I went to view the Computer properties to confirm if it would say so there as well.
To my surprise, in the Computer properties, the Operating System now registers that I have 4.00GB of RAM installed. I was immediately overjoyed at the prospect of having an additional 668MB of RAM to play with... Yes, I am a child!
So I opened Task manager to be greeted by the familiar 3325MB of memory available. Too good to be true? I will search about to see if this issue has been documented and is being looked into after all this time...