I have the 2011 11" MBA (i5, 4GB, 128GB) and also the base 2011 15" MBP (i7, 4GB, 500GB). I can't justify keeping both, but I am really torn on which one I want

I have the 2011 11" MBA (i5, 4GB, 128GB) and also the base 2011 15" MBP (i7, 4GB, 500GB). I can't justify keeping both, but I am really torn on which one I want to keep. On the one hand, I love the portability and speed (due to the SSD) of the Air, and it feels almost like a desktop when it's plugged into the 20" monitor on my desk and connected to a USB keyboard and Magic Trackpad. On the other hand, I really like the MBP's beefier CPU, discrete GPU, and much larger HDD; the Air's 128GB HDD really feels limiting to me (since photography is one of my hobbies). The HDD does make it feel a bit slower than the Air in some ways, though. I'm looking to get rid of my desktop Windows PC since I don't use it very much anymore, so that leaves me with two options as I see them: either sell the MBP, keep the Air, and get a Mini for the extra space/network storage, or sell the MBA, consolidate everything into the MBP, and maybe upgrade it with a SSD and kit from OWC to replace the SuperDrive with the spare HDD. I'm really not sure what the best way to go is, since I like both systems a lot for different purposes.