My opinion:
the macbook air= very lacking.
what people don't seem to realize is that the macbook air was made for the people who travel constantly, but it is most lacking in that area.
For example, consider the non-usereplacable battery. People who travel a lot with their laptop tend to go on for hours without being tethered to a cord, what happens when the battery runs out?
The air has the same size footprint as the macbook, and that is what determines portability, not thinness.
Anyway, once you add the external dvd drive, usb hub, usb to ethernet converter, and mini dvi- vga/dvi converter (these are standard ports on most laptops only a pound heavier), you have a laptop weighing close to 4 pounds!