I must say that the new 2013 MacBook Air with the Haswell processor is incredibly good! I haven't bought one myself, but I've seen a lot of tests of it on YouTube, and it beats every mobile computer on the market when it comes to speed and battery life. It even beats the Retina MacBook Pro. The SSD's, the processor, the battery makes the latest MacBook Air's freaking awesome! I mean 9 hours battery life for the 11-inch, and 12 hours for the 13-inch! Unbelievable. But Apple never lies about battery life. It is exactly right. And I actually saw a battery test of the new 11-inch that even had one hour more than what Apple said! In the test they played a quicktime movie over and over again until the battery died, and it managed 10 hours! They tested the 2012 model that I have in the same test and it had 5 hours.
So if you are after a new computer this year, go for the new 2013 MacBook Air! I highly recommend it.