As much as I like the idea of a MacBook Air, the fact that my part-time job is classical CD critic means I need a computer that can play compact discs. That's how they come in the mail and I need a computer that can play 'em.
Also, $1000 for a laptop... gack!
Despite its awkwardness, and the fact that 3G costs so much per month, the iPad is more tempting to me.
I travel a lot for work, so I'm looking for something that is light but doesn't sacrifice productivity. I can't imagine editing a 20 page document on an iPad, and I need something to run our apps for statistical analysis and project management, so I'd be much happier with an Air (I have a Macbook Pro now).
Apple does sell a USB CD/DVD drive for around $70 (burner and reader). There is also a CD drive on Amazon for $13 though I'm not sure if it works with the Air:
http://www.amazon.com/External-MacBook-13-inch-17-inch-MA090LL/dp/B003D1F9YA