Just to add a small correction - the air does not have 'top of the line' i5 or i7 processors. Rather, they use a slower, dual-core mobility model. I'd also argue that it is 'cheap' - but that's more of a relative point. :)
$1199 ($50/100 off if you're a student) as configured. Show me another laptop with it's form factor and capabilities for that price? Hell, show me another laptop with it's form factor and capabilities?
$1000 for some so convenient is a STEAL, especially if you actually make money using it.
That being said, in my opinion no other ultra-portable comes close to the Macbook Air. If I could justify having two laptops I would be ordering one right now instead of typing this.