DocPad

DocPad is a superior alternative to Notepad. Although it fills the same role, plain text editing, it has many advantages: 10-level undo, alphabetization, block indent/unindent, bookmark, case conversion, encoding conversion, file history, jump to line, jump to offset, keyboard macros, search and replace, spell checking, statistics, variable pitch font, and much more. It also includes a built-in calculator, calendar, and character map. Used internally by Gammadyne for 4 years, DocPad is now available to the public for free.