With Ockham's Razor, fourteenth century logician William of Ockham basically stipulated that "...all else being equal, the simpler of two solutions will be the better choice". Renaissance icon Leonardo da Vinci later declared that "...simplicity is the ultimate sophistication". And a twentieth century poet warrior observed that "...perfection is attained not when no more can be added, but when no more can be removed."
Web design is a mixed discipline--part art, part science. Those parts often work at cross purposes. But in the words of wisdom above, they converge. Nowhere does the K-I-S-S principle apply more so than on the Net. There are exceptions, but most Web surfers are busy people with short attention spans. A simple message will penetrate faster than one that is complex or complicated. A clean layout will convey that message better than one that is convoluted or cluttered. And the delivery should be effective regardless of device (PC, Mac, iPhone or other), agent (Internet Explorer, Firefox, Opera, etc.) or screen resolution (e.g. 800x600, 1024x768, 1920x1200).
For web design with RE$ULT$ in mind, "Cool!" is only cool when it is also clear, concise and consistent across all relevant media. Let us show you the elegance of simplicity ... and vice-versa: