Coolest is way too subjective so I would mention some cool (meaning very functional and good looking) ones:
Asus W1N, Asus M6Ne, Samsung x30 (very very expensive though), Sager 3790, Mitac 8050, Acer Aspire 2020 and, of course, the highly coveted PowerBook G4s
The Acer Ferarri may seem cool to many people because of one single feature - its red color - which steals the attention away from the rest which is pretty average. However, for many others it is the red paint that spoils the package and makes it look childish. basically you either love it (in your teens or early 20s) or hate it (when you grow up).