I can really recommend having an i7/64Gb desktop with native Linux OS as your primary development environment. It is like 20x faster than a Macbook Pro/8Gb with Linux VM.
And you could keep your Macbook Air for looks [and ssh to that box] ;)
this is what I do now at work. It has totally changed the way I do development. Instead of having a "build farm" or separate box to run continual tests on it's all in the same machine. SSHFS makes a world of difference too.
And you could keep your Macbook Air for looks [and ssh to that box] ;)