Which 15" MacBook Pro will be best for my planned use?

Question

I am heading back to school and am required to get a MacBook Pro for class (I am a Design, Art & Technology - AKA Multimedia - major).  The suggested specs from the school are as follows:
15-inch MacBook Pro
2.7GHz Quad-core Intel Core i7, NVIDIA GeForce GT 650M with 1GB GDDR5 memory
8GB 1600MHz DDR3 SDRAM - 2x4GB
750GB Serial ATA Drive @ 7200 rpm
I am in the process of researching if this is the best computer for my needs.  I am upgrading from my current laptop - a 2.53 GHz 15" MacBook Pro from '09 with 4GB of RAM and 7200 RPM 750 GB HDD (upgraded from a 5200 RPM 250 GB HDD) running 10.6.8 - which has been holding up great for four years.  At this point though I need a second computer that has a quadcore processor.
My normal/expected usage:
I will likely be working on projects in web design, some light game design, app design, interactive installation, etc. for class.  I anticipate working on video editing software and Photoshop as well.  I regularly use Ableton Live with an external audio interface, MIDI devices and third party plugins for music production (20 to 40+ track mixing & mastering) and may start to use it for live or interactive projects.  I run an external monitor as a second screen when at home and do a good amount of multitasking work with the second display where quickness switching between applications is key.
I stopped by the local Apple store today and had a conversation with one of the sales reps exploring the possibilities of deviating from my school's suggested bundle above.  We talked about the benefits of SSD's on performance but the drawbacks on storage size to $$ ratio (I need at least 500GB of storage space, preferably 700GB).  The rep suggested multiple times that the Retina display model would be best for me because it is a more durable computer and makes more sense than dropping the 2.7 GHz processor to a 2.6 GHz on the above recommendation and using the money to upgrade the hard drive to an SSD (since it would be a similar computer but without the hi-res screen).  But the Retina models were in stock, while the custom non-retina model I was considering building online was not, so I do not know if the rep was just doing his job as a salesperson and trying to move what the store had in stock...
What I am hoping to get opinions on is: Given my planned usage, will the school's suggestion be sufficient/will my downgrade of proccessing power to fund an SSD be insufficient/does it make sense to really stretch my budget and get the Retina 15" 2.7 GHz with 8GB RAM and 512/768 GB SSD?  Even with the educational pricing and my usage, I don't know if the upgrade to the Retina 15" is justified - but I am not very experienced in comparing computers.  Any thoughts or suggestions?  Thanks!

Answer 1

I say DITTO to what Clinton just told you, AND what woodmeister said.
As to use of the External HD  use same for all large media files, PDF , pics, movies etc.
Keep your internal SSD for programs and primary (use it every day) working files of small size.
Yes, I would replace the SSD as upgrade and RAM myself.
Ram takes 30 seconds to do, anyone can do that nearly with eyes closed.  EASY
SSD, youd need to use carbon copy cloner or likewise, clone your internal HD to the SSD, check with a boot to make sure all ok........then install the SSD, very easy, like Clinton said, .....done it many times.
You asked:
Are you able to reference info on them without moving the data to the internal SSD?
Yes, you can alter, open close etc files off the external HD same as you can the internal SSD, however access speed will be slower, but plenty fast enough for anything you want to do, watch movies off same, work on/ alter/ create files on internal and then backup to external
You need an external HD at any rate for Time Machine backup, and backup in general. NEVER trust any internal HD, or a single copy of anything.
In fact you should always have at least 2 backups for data, in which case a 2nd external HD is highly recommended.