There comes a time when that giant, corporate-issued laptop stops fitting into your lifestyle. When dragging around a Kensington roller case just won't do. When you start to hear the siren lilt of something thinner, lighter, and maybe a bit more alluring. For years the MacBook Air has been that svelte temptress hollering your name, but it's always been a bit too slow -- all show and no go. It didn't have the power and the longevity to make it a serious contender for your serious affections.