You're all over the place here. First of all, you're confusing memory (RAM) with hard drive space. They are two completely different things. The MacBook Pro with Retina display uses flash storage as its hard drive. A non-Retina MacBook Pro (aka "Classic") can be upgraded to this type of storage as well. Aside from the screen and a few other physical differences, the underlying hardware of the non-Retina and Retina 13- and 15-inch models are identical. The standard 13-inch Pro and Retina have the same CPUs, integrated graphics processors, and can be ordered with the same quantity of RAM. Same goes for the 15-inch Classic and Retina.
However, with a Classic MacBook Pro, you are able to upgrade the hard drive and RAM yourself very easily and with comparatively inexpensive 3rd-party components.
The only way to upgrade the RAM on a Retina model is to order it from the factory that way. It is impossible to change yourself. Similarly, the Retina's flash storage module is a proprietary unit that can only be replaced with either an Apple original part or a module sold by Other World Computing. Both would be considerably more expensive than simply ordering the machine with these upgrades straight from the factory.
With that out of the way, if you're going to be watching movies and installing software via DVD/CD, I would suggest the Classic MacBook Pro because no Retina model includes an optical drive. Look at the entry-level 15-inch model and upgrade to the high-resolution display. Whether you prefer glossy or antiglare is up to you.
