John Gruber talks about the MacBook Air’s place in the Mac lineup, and comes the following conclusion:

Here’s the way I see it: the Air is a secondary Mac; MacBook Pros are for use as a primary computer.

[…]

The new MacBook Airs—particularly the 11-inch model—don’t compete against the other MacBooks so much as they do the iPad. It’s like a ‘pro’ solution for the same ‘in between a smartphone and a full-size laptop PC’ market segment that the iPad sits in.

With iOS device sales outpacing Mac sales and the MacBook Air pricing being surprisingly aggressive, it’s looking like 2011 will see an increasing number of ‘second devices’ that rely on a ‘main’ Mac or PC. It’ll be interesting to see if anyone can figure out some way of dispensing with the hub—it’d be great to be able to just have a couple of iPads and a MacBook Air knocking around, relying on some kind of networked storage for holding large files and back-ups. Right now, you can do this with Macs, but not with iOS devices, but I reckon it’s only a matter of time.