I'm an example of this. I'm a .NET web developer but if I need to make a quick view (css/html/etc) change, I'll fire up Notepad++. It's way faster than firing up good ol' VS. NP++ is also good for more complicated/repetitive text editing.
I'm also a .NET developer. But your usage there to me falls under what I called "scratch pad". As in NP++ is not your main means of writing code. I always have NP++ running so I can throw things into it as needed.
