I saw today a great example of using XUL (XML User interface Language). The pointer is from Digg. It's an application that searches Amazon and displays results in an elegant way. It looks like an entire seperate program. Try it, it's amazing. If you are programmer, get a look to the source of the page: In firefox CTRL-U.
If you are in web design, you certainly know that learning to put together colors in a harmonious fashion is one of the most important skills of a Web designer. I have seen ( done :-) ) very poor design with colors that look so painful together.