The world's thinnest laptop: Acer Aspire S5

...or rather Ultrabook

Unveiled at CES 2012.

Screen: 13"
Thickness: 15mm (at thickest point), compared with the MacBook Air's 17mm.
Weight: <1.35kg, the MacBook Air weighs 1.35kg.
Top feature: Thunderbolt port, Acer's instant-on technology, powers up the laptop in 1.5 seconds.