This topic comes up every so often in online programming communities. It can elicit passionate discussions and even small scale wars (VIM versus EMACS anyone?). No coder worth his or her salt should be without a favorite(s).
My current personal favs are Notepad++ and VIM. If Notepad++ were supported in Linux and Mac environments then I wouldn't need VIM.
I love the customizeability of VIM but after wrestling with it for a couple of months I gave up trying to use it exclusively and went back to Notepad++ in Windows.
What are yours?