I think the current macbook air is great for a portability factor and other aspects.
i dont have one currently but i will probably get one in 2-4 years
this is what i would hope it to have
2.4ghz intel core 3 duo
solar rechargeable batter with 10 hrs fully charged with wifi on
full length touchpad covering the bottom pat of macbook air touchpad
OLED screen with ssd backlighting, 120hz and a resolution of 1900 X 1200
2 usb, 1 firewall