Missing the point slightly
I have had my 11" Air since December 2010, and find it to be a very capable machine. However, I don't expect it to be a desktop replacement (or even a full-featured laptop replacement). I bought it because I travel a great deal by train (1.5 hour commute each way daily, plus regular 12 hour jaunts between my places in Switzerland and France), and I needed something that I could sling into a bag, pull out and use with the minimum of delay, and on which I could comfortably research the Web, cut and paste into a word processor and presentation programme, and do some light trimming and colour balancing video and photographs. At the time I had just had an Acer Aspire One fail on me (largely due to the physical abuse it got during travel), and I had just bought an iMac, so I was interested in standardising.
My choices at the time were MacBook Pro, MacBook Air or iPad (which was about the same money to get the same amount of storage, 64Gb). The Pro was too heavy and expensive, the iPad lacked a keyboard or any decent software (and needed a stand to watch movies), but the Air fitted the bill. Aluminium body for strength, decent keyboard for touch typing, clear screen, and decent wireless communications. I bought an Ethernet adapter, but I think I have used it three times. Sure, the SDD is limited in size, but this isn't a machine for long term storage. Yes, my iTunes library is too big, but the speakers on the Air aren't up to listening for very long. Yes, I can't fit many DVDs on it, but the screen is too small to watch anything comfortably anyway (as would a 13" screen be, if my experience of other laptops is anything to go by).
So, as a travelling companion to a bigger and better desk bound machine, it's actually very good: rugged, light and powerful enough - and mine is running a much less capable processor than the new ones. I'd still buy one now, even though tablets are much better than they were, because with a tablet you still need to get a good keyboard and a stand in order to work for more than a few minutes. I might be tempted by some of the Ultrabooks, but they aren't hugely cheaper (and with the exception of Sony and Lenovo, build quality is usually very poor), and I'm finding the Windows world too bloody frustrating over simple things like driver and codec compatibility. Say what you like about Apple (and there is much to criticise), their products either fail very quickly or run forever - and more often the latter.
And before anyone accuses me of being a fanboi, let me recount a tale of two REAL Apple nuts. As I said, my Netbook had just suddenly died, and I was booked on the train to France for two days hence, planning to get some serious work done. So I nipped out during lunch to buy the Air, and on my return two of my colleagues (one male, one female) independently of each other actually made cooing noises as they stroked my new computer. Not something you'll find me doing.