Java - Cool, practical, well documented, and good free development environments available
Mathematica - More high level programming language, "just do it", go and concentrate just at the problem, there is no need to spend time with extra coding
C (not C++) - Simple and clean - for OOP it is better work with Java (more fun)
SQL and PL/SQL (Oracle) - Big problems with data can be solved at the database level, quickly fast, trustworthy and practical.
Look for the right tool for the right job, and do not spend time.