I actually find a few obscure assemblers or odd DSP chips to at least make a CV interesting, C on small cores should be a given...
However my number one interview question is "What have you built?", I actually tend to care about this far more then the details of some chip you may or may not know, I mean you will spend you whole career learning new chips, new languages and new ways of doing things, that is a given in engineering and is largely what makes it so cool.
I want to see the lessons that only come with building things, steam train, computer, rocket or treehouse I don't much care what you have built, but show me a passion for designing and making things and tell me what you would do differently if making that thing again (If there was a team involved, even better).
Maths, at least to the point of recognising the methods (I assume you are actually going to use matlab in reality), electromagnetism, DSP in a sort of Z transform and numerical stability kind of way, computer architecture, communications, some analogue some semiconductor physics, all that stuff is important, but without the desire to make things it is a route into financial services, not engineering.
Regards, Dan.