I've been programming professionally since 1984 in a variety of areas, from assembly language interrupt handlers to Java web applications.
I far prefer Unix based systems, including Linux and Mac OS X, over Windows — I've seen people spend hours of repetitive mousing around a GUI for what I can do in under a minute at a *nix command line... but I've programmed on Windows, OS/2, MacOS & OS X, a wide variety of Unices, and VMS
Currently doing web apps using Java, Spring, Hand-coded JSP/HTML[5], Javascript + jQuery, MySQL.