MB Air:
Light + Portable + Better Screen Resolution + No Optical Drive + RAM is not user upgradeable.
MB Pro
Portable + Optical Drive + RAM and Hard Drive is user upgradeable.
Now, if you want to be able to upgrade your RAM to 16GB for what you'll be using it for, then the MB Pro is for you.
If however, you like the idea of having something very light and are fine without the use of the built in optical drive and are happy with the 8GB RAM that is not user upgradeable, then go ahead with the MB Air.
In any event, regardless of which one you end up purchasing, I'm sure you'll be happy with either one of them.