[jckarter]

Every Mac still ships with Xcode on the OS install disc, as do the OS X upgrade discs. Let's wait until Lion comes out before assuming that won't be the case anymore.

[electrum]

The MacBook Air doesn't ship with Xcode.

[dpezely]

I have a current model 11.6" Air purchased in January, and Xcode was pre-installed into /Developer.

This was a stock machine: walked into Apple Store to buy it. (No special factory config)

Compiling SBCL and a few items from MacPorts worked fine, so everything seems consistent with what I've seen on other Macs since 2005.