This post is a bit old, however I'd like to throw in my ideas. I have worked in embedded programming since the early 1970's and here's what I have found as a general rule.
First, micseydel is absolutly correct when he suggusts you should learn C. You may have to learn some assembly language later for specific applications (and MCU's) but for the most part, all of your programming will be in C.
This holds true even if you get into integrated circuit design (There are special libraries that are used for this, but most are in C).
You can divide this field up into parts, I won't be able to list them all, but here's a shot at it.
o Automotive computers - This is a huge field you can look to companies like Alegro for information. I never had an automotive application, but know Alegro's products are akmost exclusively for automotive
o Industrial computers - Many companies are involved in this field. and the field can be broken up into sections itself. There are power considerations, some applications (like cellphones and field equipment require a very low power drain. In this case, Texas Instruments has until reciently won the battle hands down. They sell a series of ultra low power drain MCU's (The MSP430 is an excellent example) These come loaded with devices (A/D converters, Comparators, timers, etc.) and are extremely inexpensive (on the order of pennies each in larger quantities.) You can get a development system for less than $20.00 The good part is that information on how to program the different devices (or different parts of LSI chips) is freely available. They will give you a suite of development tools including compilers and several choices of IDE's to go with them if you are a student, or if you have a design in mind. Take a look at http://www.ti.com/ww/en/launchpad/launchpad.html?DCMP=mcu-launchpad&HQS=launchpad for some of their launchpad development boards.
o Microchip carries a huge line of 8 bit through 64 bit industrial MCU's. Again they have a plethora of information available on each device, and low cost development boards. Their 'PIC' line has become famous. See http://www.microchip.com/
o Intel has been around for a long time, and have some devices designed back in the 70's that are still in wide use today. The 8080 and 8051 mcu's inparticular have survived. There LSI is second to none.
o Motorola still has a large selection of devices for the communications industry. The first Macintosh computers from Apple used Motorola 68000 processors, prior to that, their apple 5-E's and even their first device (which sold it's case as a separate item) used 8 bit Rockwell 6502 processor.
o Instrumentation - Huge field everything from Oscilloscopes to Plasma, Atomic Absorption and Mass spectroscopy (my field).
o Sports devices - my last contract was for a 4x4 matrix keyboard for Hummingbird Fish Finder.
o This is a supplier, but a good place to look for manufacturers: http://am.renesas.com/
o And likewise http://www.digikey.com/
o and again http://www.mouser.com/
o one more http://www.alliedelec.com/
o and many more companies that you will discover
You should look at the application notes and ideas provided by these companies as they layout pratical applications that can be done in a dorm room is almost always available from the manufacturer
In all cases, the 'C' language is used for programming. Some Pascal is still used, but in limited applications.
A great place to look for information are the many publications that are available free of charge to students and the trade. a few are:
Sorry for the rambling. It's my favorite thing to talk about. Hope you find something interesting