I am going to sell my iPad 2 and purchase an ultimate 11-inch MBA. After having the iPad 2 for a couple of weeks, I feel that even the base model MBA is a much better buy.
The MBA update is so close, I don't think I'd do that just now.
That is your choice. To me the iPad2 is a great Internet Appliance while the MBA is a poor excuse for a laptop.
If all you want to do is cruise the Internet the iPad is your best bet but if you need a computer, get a real computer.
I have had the iPad 1, iPad 2, 13" MacBook air and multiple 13" MacBook pros. The MacBook air was a worthless computer simply because it's only advantage over the pro is being a bit thinner and a bit lighter. The pro is the better laptop in every way. Neither of them compete with the iPad simply because the MacBook air you want to buy will be lucky to get 5 hours of battery life in real world use and the iPad gets 10 hours no matter what. To me that is the difference between being tethered to an outlet or not and so the air is practically not even portable since you need to drag the ac adaptor evywhere you go.