I've just built a machine for my son (a professional photographer - stills) and can tell you Adobe is a resource hog like you've never seen before. I wouldn't have even considered a laptop except perhaps the Macbook Pro, which is horrendously expensive.
I did use a 250GB SSD for the operating system and Adobe, but put in two 2TB hard drives for storage. It also currently has 16GB of RAM, which doesn't seem to unduly affect performance.
You also need a fast graphics card to supplement the CPU to render the graphics.
It's not connected to the Internet intentionally, so no anti-virus software is loaded which again can slow your system to a crawl. It's a machine with one purpose - to edit photographs as quickly as possible.
It depends I suppose, whether you're going to use such a machine professionally, or whether you're just editing the occasional video. If the later, you may wish to accept slower performance for the convenience of a laptop and Internet (gaming?) capability, coupled with the overhead anti-virus software creates.
The bottom line is, buy the fastest machine you can afford, because you'll need it.
I can't comment on Widows 8 as I detest it and wouldn't go near it. As it is, Windows 7 works fine.