I've started recently with LISP and it's been a rewarding experience. I've noticed that it's just more flexible than the C-like languages. For example, I have been able to get the factorial of a number as big as 3000 in a very short time! That was simply not possible with a C-like program. I've used Emacs with the "Superior Lisp Interaction Mode" preloaded, upon the suggestion I got from useful book "Practical Common Lisp by Peter Seibel" (It's available on line at gigamonkeys.com)<p>I have also acquired the book "ANSI Common Lisp by Paul Graham", which is a classic and no-nonsense book. I personally find Paul Graham's approach quite refreshing.<p>Having seen Ruby being employed in various environments, I've also started to learn Ruby. It's a multi-paradigm and dynamic language and hope to use it in a RoR application development. It kind of forces you to think dynamically and that helps you to write more efficient code, I guess.<p>So far, I couldn't find enough time for either Java or Python.<p>And oh, lastly I must say: C++ with templates (STL) is quite indispensable. If you master C++ with all its features like STL, you'll find that it can handle a whole lot of things quite elegantly.