Macbook Air is exactly what you need: AH! :)
Macbook Air could really be the super-laptop that satisfies your needs, but the guys at Lenovo do not agree with that.:)
Let me just say that the both have a whopping price; they're really insane expensive, especially for an unltra-portable that you're supposed to carry everywhere. Check out the Asus EEE instead, and save 2.000 USD.