Is it simple, clean, and provide a lot of whitespace? Is it based on only a few solid colors and provide an intuitive and quick method for completing its task?

Is it simple, clean, and provide a lot of whitespace? Is it based on only a few solid colors and provide an intuitive and quick method for completing its task? If so, I like it. I really buy into the whole design-for-your-product idea. I also really appreciate clean lines and a lot of whitespace. Good contrast, like tasteful transparency, can do a lot to make your site look professional as well. Most importantly, though, your site has to be useable. If you have a 4 MB background image and use MySQL with all the defaults, I don't care what your site looks like, its gonna be too slow for me to use.