A knight would for sure carry his sword proudly and ready for any battles. But then he can not use such a heavy weapon for daily tasks such as peeling an apple. Sometimes I think the same with ourself as programmers. We need a stable, strong and static typed programming language that can get us the heavy job (large project, and enterprise system) done in more manageable way. But yet, we face many smaller daily tasks (eg: parse a text file for a search value, or generate sample data etc) that is better fitted to use a lighter, dynamic language because they are faster to write; and the code need not go through heavier process as the main project.
Through out my career, I have been keeping two languages (one strong typed and one dynamic typed) pair very up to date. I would learn it and be proficient with it enough to write code without flipping through a book. I started with C++ with Perl and then switched to Python. And then later with Java and Jython, and later with Groovy. These are my strongest languages that I used the most, especially with Java. Of course I never stop learning other languages as well, such as Scala and Ruby etc. I personally think Ruby is very nice and good language to learn and use. I just not have had a chance to use it that extensively yet. Mastering a full static language such as Java would take much longer time, but one can learn a dynamic language fairly quickly.
Any rate, if you a programmer, I strongly encourage you to learn at least two languages, and learn it well. As I said, prefer one static and one dynamic language. This pair of combination will boost your productivity to next level.
