fn key
You get used to the fn key location, although I tend to use my thinkpad keyboard most of the time now. They're good keyboards.
I used to get really annoyed about the lack of a windows key. Glad they have them now.
I personally couldn't care less if my keyboard is backlit, although I must confess to having a backlit keyboard for my home PC. It's useful for gaming in the dark but not really for typing. Unless you don't know where the keys are.
What I want from a laptop is a high resolution screen, decent battery life (with batteries that you can replace/upgrade), and the smallest size possible in relation to the screen size. Plus decent CPU/RAM/GPU etc of course.....