rMBP for animation student

I'll be heading to college in August, and I'm going to buy a new Mac soon. (This will be my first personal Mac, so I'd like to have the summer to get to know it before class starts.) I'm studying animation, so I'll be doing 3D modeling and animation, video editing, etc.

I'm currently debating between the 13- and 15-inch rMPBs. For those of you who have more experience:

- How important is the extra screen real estate?

- Would there be a noticeable difference between the base model 15-inch and the 13-inch upgraded to an i7?

- Is the standard 8 GB of RAM sufficient or should I upgrade to 16?

- Are dedicated NVIDIA graphics worth the price?

If you're wondering, I'm going to make sure that WWDC is within the 14-day return window when I buy, just in case updated models are announced. From what I've read about Intel's roadmap, this seems unlikely, but I want to be safe.

Edit: Thanks for your help, everyone! You've convinced me to wait until WWDC to see if any graphics updates are announced.