Paul Stamatiou, on using the Macbook Air as his primary computer for a little over two weeks:
"I have been able to do everything in my daily work on the Air. This includes using multiple spaces, constantly streaming iTunes radio music, using many tabs in Safari, casual Photoshop use, taking notes and recording lectures in Word 2008, watching episodes of Top Gear and doing web development with Firefox."
(Source: Review: MacBook Air)