This might come in handy for HTML coders using Notepad++...
When a color value is typed in (#RRGGBB), the font color for those 7 chars is changed to the color represented by the values. The text could be outlined in black or white if it matches the background color of the notepad++ window to make it more visible.
Alternatively, the '#' could represent the final color, and the individual color values (RR, GG, BB) could be colored from black (if 00) to Red, Green or Blue (up to FF).
the '#' has the color '#ff00c0'
the 'FF' has the color '#ff0000'
the '00' has the color '#000000'
the 'c0' has the color '#0000c0'
Another variation would be to display a small solid square (size relative to font size) next to the color code, which displays the color. When clicked on, it opens the windows color picker (if windows has one built in?)
This could possibly be extended to cover other ways of representing colors as well (like percentages etc..)