Last year our CS department put on a lecture from the head of Epic Games, makers of Unreal and -- surprising as hell to me -- a local company. Really, a facinating discussion of the industry. One of the pieces of advice he offered that should be most valuable to you is that you get working on personal development projects NOW. When you're applying to jobs at those places, if you can show them proof that you're already competent in the areas that they're working in, they'll likely be very interested in you. Education is nice, but they'll LOVE you for experience. Heck, one of Epic's programming heads doesn't even have a bachelor's degree; just an utterly wicked set of skills for programming.
The master's degree certainly can't hurt and will give you a chance to specialize a little more in the graphics area. But, really, if you want in to a company like that, start the work on your own right now.
-- Jack
Cats are intended to teach us that not everything in nature has a function.
-- Garrison Keillor