I write quite a bit in plain text files. A simple text editor, like Notepad, meets most of my needs when writing plain text files.
But sometimes being able to bold or italicize a word is very useful. And being able to indent a section of text is a big plus. Outside of that, I don't need much for these documents (see this question for when more is needed). A spelling checker is a plus, but definitely not essential.
There are tons of great notepad and word processor programs out there, but most are overkill for this simple purpose. Really, all I need is bold, italicize, and indent.
I would like to save the file as a plain text file (with appropriate markup or Markdown, which will be needed), or if I absolutely have to, as an RTF (Rich Text File).
I want the program to be Windows 7 compatible, fast, lean, free, and preferably portable.
(I've tried Jarte Portable, but it only handles RTF or completely non-formatted text (no markup), and there is something about it that after it starts, the cursor spins like it is busy for 2-4 seconds, which I know is a bit picky, but I find momentarily interrupts workflow.)