There are really only two types of programmers. Those that use only a basic editor. And those that use an IDE (integrated development environment). I began as an editor-only guy nearly 20 years ago only because IDEs were few and far between. But over time, as I began doing less CAD-only development, I began warming to the whole concept of IDEs -- especially as I began focusing more heavily on web development. As a result of that, I've become a big fan of the Microsoft Visual Studio IDE. Unfortunately their CSS editor has always been the weakest part of an otherwise strong package. Since I'm doing more and more CSS-based design these days, I needed to solve that short-coming.
I recently checked out the trial version of TopStyle Pro, and after just a few hours of use, I bought a license. Its interface is very similar in its look and feel to Visual Studio. The default CSS editor view is a multi-paned view with panes for CSS Selectors, Clip Library, Style Inspector, Output Preview, and a central tabbed Code Editor pane. Like any good IDE, the editor does a great job of anticipating and facilitating the coding process without getting in the way. The feature I use most often however is a preview window that allows a side-by-side comparison of your code in both IE and Firefox/Mozilla.
Although I use it primarily as a CSS editor, it is also a strong HTML/XML editor as well. It also provides mo facility for server-side scripting technologies such as ASP, ASP.NET, PHP, or Cold Fusion, but I don't see it as a drawback I'm happy with Visual Studio for that. But if you're looking for a strong CSS/HTML editor, check out TopStyle Pro. It's tough to beat.