Hey man, just curious as to why you switched from a MBA 11 to the rMBP 15 - I've seen your previous setup on another thread a while back. I'm currently in the a similar position, contemplating on whether to make the switch, afraid of regretting it later on. Did you by any chance consider the rMBP 13 when you bought the 15? How do you find your setup now compared to when you had the 11? Any regrets?
Actually, It went like this (chronological order):
27"iMac + MBA 11" 2011 model
11" MBA 2011 model + 27" TBD
Antiglare MBP 15" 2011 model+ 27" TBD
15" rMBP + 27" TBD
15" rMBP + 27" iMac.
I bought a 11" MBA because I had an external 27" screen (first iMac, then TBD). I decided to purchase the 15" Antiglare MBP simply because I was offered one at a very good price and decided I wanted one Mac with more power (thus switched to 27" TBD). The switch to the rMBP was because I wanted to retain the screen size and power while going retina, thus the 13" rMBP was no option.
I then sold the 27" TBD because I could (re)-purchase an 27" iMac without paying more than what I sold the 27" TBD for. Don't ask me why. The use of Dropbox makes storing my documents and all so easy that I often don't notice where I edited one document.
So, in the end I'd say I loved the size and weight of the little Air, but the 15" rMBP is perfect for me. it's not heavy by any means and offers more power, screen size, resolution etc etc and still in a thin package.