In the six years I've been using Macs and Mac laptops, I have never been as enthusiastic about a new product as I am about my 11in MacBook Air. I've praised it many times, but the blogosphere seems to have fallen in love with it – particularly with the 11-in configuration. Here are two more excellent reviews which are worth reading.
The second review is particularly interesting and includes links to screenshots showing how much real estate you have with the small screen because of its higher definition. Certainly you don't feel short changed with any aspect of the new mini Air. Its weight and size are right on the cusp of what you hare happy to carry around; taking it out for the day is a no-brainer whereas with anything heavier (such as a 13-in MacBook Pro) you have a difficult choice to make.