I just cannot afford it for her yet and that's my biggest complaint about the new slender notebook from Apple. Initially I had more complaints, such as, a battery that you cannot remove, a small hard drive, a lack of an optical drive and a shortage of external ports (there are only three: USB, headphone and video.) Many computer pundits shared my original point of view. I thought of the Air being suitable only as a secondary computer for the well off.
However, after some reflection and reading some other blogs on the subject I have since come to a different conclusion. While the MacBook Air may not be for me, a power user that dabbles in video editing, running multiple operating systems, programming, web development, running virtul machines, creating DVD's and the such. The Air is perfect for my wife.
Her main computer tasks are reading email, browsing the web, watching episodes of her favorite television shows when she misses them (Grey's Anatomy, Ugly Betty, Desperate Housewives) and sometimes working from home via the Citrex remote Windows client for her office computer. She'd rather not sit at the desk preferring the sofa or bed. So wireless is a must and a backlit keyboard and reduced weight are nice options.
She does not need a large hard drive and she would never remove the battery. While the processor is the slowest in Apple's computer line-up it is still many times faster than Intel's Pentium processor which many people are still using for basic computing tasks.
So, while the Air has it's detractors, my answer to them is that Air was not meant for you, just the way the iPod is lacking in features (FM radio, voice recorder, support for OGG, etc.) for some while the simplicity is more appealing to many others.
As another blogger put it, the Air is like a sporty convertible coupe. It is not practical for everyone, but for some it gets them from point A to point B in style and comfort. Now, when Apple lowers the price it will become even more popular, like the Mazda Miata. I suspect that the price is due in part to the processor that Apple had Intel custom build for them.