|The newest VC will not be able to fit in our old laptop (with PCI E) because of the power needed by the new cards? Is it this?
Yes. Notebook CPUs and GPUs are a lot less power consuming than their desktop equals, but the notebook environment is a lot less flexible as well. Differences of 5 or 10 Watt in a component, hardly noticable in a desktop, can lead to trouble in a notebook.
Marketing departments have been shouting "modularity" for the last 15 years when they needed another selling argument. Fact is, that notebooks nowadays aren't built much more modular than my first laptop, a 486 with whooping 33 MHz and a black and white screen.
Buy a notebook that fits your needs, just don't count on being able to upgrade gpu or cpu after a year or two.
Don't get me wrong: PCI Express is a great new bus for computers. Especially workstations and high end PCs will profit.
But I doubt that it will give us greater modularity in notebooks. If producers had been willing to standardize graphic cards, they could have done it with agp as well.
And don't forget: Even if the components are connected via pci express it isn't sure that they are removable at all. PCI Express is a bus system, it is possible to take advantage of it's performance by soldering the components to the mainboards, without using sockets or slots at all. They will use soldering for networking, usb, firewire, sound...
I bet there will be a lot of pci express connected graphic cards that will be soldered directly to the mainboards.