I had C, C++, and Java (among others) in college. In my opinion if you learn C++ you can do Java fairly easily. Java is very similar to C++, but it is less difficult in my opinion. The only bad thing with java is that microsoft is trying to phase it out because of the issues with sun. The good thing is that java and c are both good cross platform languages.
One language that was not required in my curriculum is visual basic. I wish I would have taken it because of its usefulness in the windows environment. It is also nice for writing macros in various MS apps. If you can learn VB with database interfacing that would be very marketable.
Also PHP is another widely used database interfacing language.
Some useless languages that I learned:
FORTRAN
COBOL
Assembler for the VAX 311
// 1337 programming sillz
#include <stdio.h>
int main()
{
printf("Hello, World.");
return -1;
}