TextPad is an excellent Notepad replacement with a stack of essential features.
An Explorer-type sidebar makes it easy to find and open plain text files, for instance (ANSI or OEM code sets; DOS, Unix, Mac, Netscape or mixed end-of-line sequences). A tabbed interface means you can work on several files at the same time. And you can arrange your tabs into multiple horizontal or vertical groups, too, great when you want to compare two or more files with each other.
You get all the usual editing options (cut, copy, paste, insert, delete and so on), of course, but each of these has been extended in various ways. So you can append your selected text to the contents of the clipboard, for example, instead of replacing it. There's an option to paste text to the clipboard as a web page, with the necessary headers added automatically. While the Insert function can add new lines, page breaks, the time and date, even the contents of multiple files at the current cursor position.
There's plenty more, too, with tools to transpose characters or words; append select lines; adjust text case, and sort, indent and realign text. A bookmark system helps you track important elements of your document. If you do still get lost, powerful search and replace tools (with regular expression support) will soon restore order, while on-demand spell checking makes sure your work is ready for sharing.
If you need more power then the program can be extended in various ways. A clip library makes it easy to add commonly used snippets of text; a macro recorder helps you to automate many TextPad operations; and an External Tools menu can be customised with your preferred programs.
And all this is configurable in some very sophisticated ways. To take just one example, you can restrict what individual Windows users can do with TextPad, perhaps preventing them editing existing files, disallowing use of the program's file management features, and a whole lot more.