Which MacBook to buy for portability/programming? (Or wait?)

I'm on the fence about getting a new retina MBP or to get a MacBook Air. I'm currently a CS student and I work part time as a web developer. I'm still using a 2009 MBP, which is fine for web browsing and such, but it's slowed down a lot, and has a battery life of only about 4 hours maximum.

I do also have a very recent desktop I built that I use as my primary machine when I'm at home, so the laptop I'll be purchasing will not be a replacement--it'll only be for use when I work away from home and when I'm on campus. Having said this, the most obvious answer might've been the MacBook Air. However, there's currently a Best Buy promotion where I'm able to get a late-2013, 8/256 rMBP for $1275 (pre-tax), the same price as a rMBP refurbished from Apple. A MacBook Air configured to 8GB RAM (using the education discount on Apple's website, since Best Buy has no 8/256 Air models), costs about $1200 (pre-tax).

Looking at the pros/cons of both models, I feel like paying $75 more is worth it for a better screen and a faster processor. Another option I considered would be to wait until a rMBP refresh, but it seems like a significant one won't occur until Q4 2014, or even Q1 2015. And even then, I most likely won't be getting as large of a discount as $225 ($75 base discount + $150 student discount).

I've put some time into doing some research, so let me know what you guys think!