If you're thinking about emulating a computer for your personal use, Nestopia is the ideal choice. Although it's not entirely free, it is completely free to download and use the Nestopia WYSIWYG text editor. Since most users will only play with the Nestopia games and not the text itself, the space provided for customization is minimal. With many users using Nestopia for personal enjoyment, this small investment will go a long way. However, if you need to use the WYSIWYG editor on a regular basis for work or school projects, then the cost of a premium Nestopia WYSIWYG emulator is certainly worth the cost.
There are other types of Nestopia text-editors, including a Java-based emulator, but for professional developers and web designers, Nestopia is the best choice. Besides having all the usual features, the Java-based emulator also includes full speed web programming. The biggest downside to this type of Nestopia home page emulator enhancer is that it's quite slow. When playing the game, you won't feel like you're playing on a computer, but you will definitely notice the difference when looking at the results.