Software Engineering

You can look at job descriptions posted by companies like Google, FB etc. All of these big tech companies which hire new grads have requirement of one object oriented language. So from the perspective of getting job, you just need to know one language very well. Java in your case should be perfectly fine. Apart from languages, the most important thing which would be tested are coding skills, algorithm & data structure knowledge and finally your CS fundamentals like knowledge of OS etc. For becoming proficient in coding & algorithms you can participate in competitive programming like codechef, topcoder, etc. You can also try to apply for Google summer of code to get experience doing software development projects.
If you still wanted to know which language would be helpful apart from Java, I would suggest Python since it is used currently at lot of new tech companies which are coming up and so learning it can be beneficial.

When I was in college, I learned Java too. It was great because it taught me how to work with compiling code and learning OO concepts.

I agree on C# as it enables you to explore so many programming concepts as well as use VisualStudio, which is a pretty sweet IDE.

What I didn't learn in college was dealing with markup and scripting languages. Not sure how the college offerings have changed over time, but I had to learn those on my own.

Some general advice would be to try different things. Play around with HTML, CSS, and JavaScript to see if you like working with front end technologies. Ruby on Rails would be good to get exposure to scripting languages and frameworks. Look at SQL to better understand databases and writing queries.

A long time ago, I had the same question about languages. My degree taught us Pascal (I am that old), Assembler, Fortran (in a 1 hour course), and I could take one other language for credit (I took APL).

I approached my advisor to complain about the lack of credit for languages. His reply: "Once you have learned these, you should just need a reference book and a couple of weeks to be able to program in ANY language, and a project to become fluent".

It is a VERY good idea to get exposed to a variety of languages (especially procedural like Java and functional like LISP/Scheme that are so different in how you think about the problem). But the basic idea is still valid... you will be able to pick up a new language on your own as you need them. Focus on algorithms and the languages will sort themselves out. :)

Best of luck, and enjoy!

Look into MATLAB and C++.