MBP w/o retina display
The Pro allows you more flexibility, more customisability (storage/memory), a built in DVD drive, more ports and a faster chip (to deal w/ the burdens of computing). If you plan on having one "do it all" laptop, you are better served with a MBP.
Besides, practically speaking, a maxed out MBP per applestore.com will set you back under $1900 versus an MBA which would set you back just over $2500.
The MBA however is elegant, more portable, and offers deeper screen resolution for the 13" vs the MBP 13" though it is my understanding that the screen on the MBP is actually better.