For C#, my main programming language, I use Visual Studio. For Java I use Eclipse and occasionally BlueJ. For C++ I use Visual Studio and sometimes Code::Blocks. For web stuff (not exactly programming, I know) I use Dreamweaver.
For calc stuff I use the calculator, but that shall soon change to my very own project, BexIDE
partially because it has custom syntax highlighting (XML defined), and support for essentially shorthand coding. Plus I plan to expand it beyond what I already have planned.