15" Retina MacBook Pro or 27" iMac

Excellent question

I am an IT manager and a professional photographer. I was faced with the same exact situation. I ended up going with the rMBP that you described. Let me tell you why.

I had for years worked off of a laptop, starting with the old G4 Titanium MacBook Pro. I used that exclusively for my photography business at the time. Eventually I needed more overall power and moved to a G5 tower, then replaced that with an Intel iMac 21". That served me well for years. Doing photo and now some video editing I needed more once again. I compared the 27" iMac and the 15" rMBP and decided I wanted the portability again. For intense work and storage I have 12TB on my desk of storage and scratch drive (3 4TB Lacie Thunderbolt drives). For everything else I can work wherever I need. The rMBP rocks all of CS6 and Final Cut Studio as well as Aperture.

I am currently researching a 27" or larger monitor to use while at my desk. For now though the resolution makes up for the small screen real estate. Now keep in mind I am not saying you should go for the laptop, just offering my view on my decision. If you do not have need to be portable then I would go for the iMac. My 21" had 12GB RAM and it worked great. The rMBP has 16 GB RAM and with the SSD it is fast beyond words. You pay a premium to be mobile, so again if you already have a laptop you can save money and get a rocking iMac that will do what you need.

Hope this helps weigh things for you.

Cheers.

Macbook Pro

I faced the same decision and I went for the retina macbook pro with 768GB SSD for Windows via Bootcamp, if you need extra real estate when stationary you can connect to an external monitor (currently using a Dell 24" whilst saving for the Thunderbolt display).

I'm a professional web developer and that gives me the maximum performance and mobility. If you are going to college then mobility could be a factor for you.

Hope this helps