Which would you rather use?
You'd think the MacBook air, right? But isn't there an allure to the musty clacking of typewriter keys? Wouldn't writing on such a device inspire you to great heights of literary achievement? I mean, to be able to write like Cormac McCarthy... Blood Meridian... The Road... No Country for Old Men... Bleak beyond belief, all of them, but demented genius is still genius.
But then again, J. K. Rowling loves her MacBook Air. She says it "changed my life.” She says she's written "everywhere, including some very strange places." That sounds cool. Oooo, strange places. Like Hogwarts? Maybe. I know I would be a very happy camper sitting in Dumbledore's quarters writing my ass off on my new MacBook Air.
Of course, if you're a starving writer whose day job requires you to subsist on a frozen pizza and ramen noodle diet, maybe the old typewriter, which Mr. McCarthy recently replaced for $11 dollars, might be more your speed, plus the genius thing, don't forget the genius thing.