Notational Velocity is an amazing, amazingly simple tool for word processing. Sure, Word is always an option, but it's relatively intensive to run when other lightweight programs like TextEdit (for Mac) or Notepad (on PC) do the same thing just as well without the frills. I tend to write things in TextEdit before copying them over to wherever they need to end up, but manually organizing and saving all of my text files can naturally get pretty annoying.
That's the beauty of Notational Velocity. It's a desktop text editing client that's got the basic features you absolutely need (or didn't know you needed) and no extra junk to speak of. It's beautifully simple, really. Notational Velocity auto-saves all of your documents constantly as you write them (and can sync with an online account for extra security if you so desire), so no more "file, save as" business. You can organize your text files with very simple tags and view them all at once in a simple, clean interface.
My only complaint? It's not called Notational Velociraptor. (A minor quibble, but still.)
Notational Velocity is super lightweight, so you can keep it open in the background without your computer getting all fussy about it. I keep mine open constantly, and while I use it for longer format writing, it's also perfect for jotting little notes or to-do lists.
And if you're not convinced yet, the official description describes Notational Velocity as "an attempt to loosen the mental blockages to recording information and to scrape away the tartar of convention that handicaps its retrieval. The solution is by nature nonconformist." Tartar of convention! Can you believe it?