Notepad++ : A notepad replacement with an MDI by Portside Programming. For basic text editing, it used to be my first choice.
SCite : A SCIntilla based text editor. Ideal for coding HTML, CSS, etc. It has great highlighting features. If you download SCite, I recommend grabbing this zip and overwriting the *.properties files with the contents. Pistos gave me this and I made one change. It modifies the color scheme used for displaying the files and adds a tabbed interface. This download is no longer available because AOL killed the "member" hosted webspace where I kept it. I'll see if I can put it somewhere else.
Notepad++ : While having the same name as the program above, this is much different. This Notepad++ is a free source code editor (and Notepad replacement), which supports several programming languages, running under the MS Windows environment.
This project, based on the Scintilla edit component (a very powerful editor component), written in C++ with pure win32 api and STL (that ensures the higher execution speed and smaller size of the program), is under the GPL Licence. It is my new first choice for editing HTML and CSS. I used it exclusively for the redesign of my website.