Ideal for people travelling
I have a Sony Z600 which I got in 2002 which has no internal floppy or CD drive, the fuss people made about no internal floppy drive then! It has a battery that lasted 1.5 hours unless you bought the long life version that was a ton weight. Had a 12" screen, which dimmed when running on battery power and was hard to see in sunlight and a non quite full size keyboard, which the letters rubbed off after 14 months. For someone who was in airports and hotels twice a month it was so much better than some Dell luggable. You soon start to feel those extra couple of pounds being hauled around airport lounges so anything that lightens the load is welcome.
I sometimes brought the external CD drive and usually put it in the hold luggage, most times left it in the office. Used the ethernet about twice a year.
The MacBook Air would be ideal for me, a full sized keyboard, 13" screen which is really bright, 5 hour battery life and a light latop. I don't care the DVD drive is external, or that there is a dongle for ethernet, I'll just use Wi-F in the hotel for the Internet. I like the multi-touch trackpad. You can dual boot Windows and OS X which is nice option too. It is horses for courses, this is a niche product for a small market segment.