I don't know anything that is phasing out the atom as of yet. I know that they are releasing a new version of the atom with one of the new code names. When I get home I'll look at my favorites and post the link to Intel's site.
Most of the new macbooks pros ship with NVidia cards. What you do say about video encoding is true, in regards to a large hard drive and a strong processor, but one thing that most people overlook is that onboard video cards share the same memory as your computer when you start to use clipping, image cleanup (IE Red eye removal) etc that gets loaded into memory and processed by the video card. This will make your processor work slightly harder. Granted running an I7 you may not notice it but it does effect performance. Investing the money on a video card will end up helping your system run smoother and faster. You will not have so many swaps to the hard drive from memory with a dedicated card. Please do not think that this means that you need to go out and get a liquid cooled dual SLI rig to do little john's home video, but at the same time if you are working with a large video or large images (300megs or higher from experience) you will notice the difference of doing it within 3 minutes and 1 minute.
I can not answer USB 3.0 with certainty. I would like to say I have seen laptops say they have it, but since I don't have any proof to back me up either way I can't honestly answer this.
You are dead wrong about W7. They have changed the kernel. Yes it is prettier than XP. Yes it does use more resources than XP. But there is alot of difference between the way it handles resources and programs than XP. I would say the difference between W7 and XP is similar to the difference between Windows 3 and XP.
I would suggest if you have a thumbdrive to check out Thunderbird. It can be set up to interface with Yahoo mail and pretty much will run perfectly in 90% of the resolutions out there. It gives an outlook feel to yahoo mail.