Matlab Components needed for Electrical Engineering Students
This is very difficult - if not impossible to answer without knowing what you will do with MATLAB. I am aware that you possibly don't know this yourself yet. So, I'm trying to give a generic answer.

These are the packages I would suggest for any installation, as they are useful for many fields:


Simulink: is very useful for process modelling and simulation. (basic installation, not all toolboxes) 
Optimization Toolbox: You will need optimization in most fields.
Statistics Toolbox: Same for statistics, it's always usefull
Parallel Computing Toolbox: Nice to speed up long calculations. I grew to like parfor very much.
Symbolic Math Toolbox: Unless you have a dedicated symbolic math software (e.g. Mathematica, Maple) i suggest you install the symbolic toolbox. It is not as powerful as the mentioned programs but a good alternative if you don't have these.
Signal Processing Toolbox: Is a nice toolbox with many features which are not only useful in signal processing
Curve Fitting Toolbox: Includes regression, splines etc. 


Depending on what you will do, the following toolboxes might come in handy:


Image Processing Toolbox: the name says it all.
Image Acquisition Toolbox: to control cameras (USB, GigE, ...)
Computer Vision Toolbox: is more for real-time image/video processing
DSP System Toolbox and Fixed-Point Designer: if you are likely to design algorithms for DSPs
Data Acquisition and Instrument Control Toolbox: if you will do measurements directly with MATLAB
Communication Systems Toolbox: again, the name says it all.


This is just a try to estimate what can be useful, so don't be too hard on me if I forgot something or you see it differently. I am of course also open to suggestions.