Since the MMD3 skin was mentioned, it’s important to mention that one of the things that makes it so successful is the fact that it is, first and foremost, a superb media player UI. Too often, skinners shoot for novelty and neglect the fact that a skin is a functional interface that helps a human interact with software.
There must be a balance between design and usability. In fact, I recommend that every serious skinner make an effort to learn about usability, especially about Fitz’s Law (Winamp skinners are notorious for neglecting this factor by making buttons too small or rivets that are mistaken for buttons).
Skins should delight users on many levels. But a user who struggles with basic functionality will soon abandon the skin, regardless of the initial “coolness” or novelty, will quickly seek out something a replacement.
This is an important factor to consider when a client plops down money for a skin as marketing vehicle with the hopes of a great return on investment.
The MMD3 skin is, in my opinion, quite usable and continues to delight the user over and over again. It’s a shining example of “raising the bar” in media player skin design; a solid balance between design and usability.