Impeccable Information Architecture for Structural demands.
UI Design itself means User Interface Design. It is basically the backbone of the visual aspects of any given website. Web designers work specifically on the aspect of giving their websites a decent enough look.
UX Design is simply known as User Experience Design. In the case of User Interface Design, it is more about cosmetics. More about how a specific website looks. The visual aspect is covered as far as UI Design is concerned.
A picture speaks a thousand words. Graphic Designing, on the other hand, makes the viewer think a thousand things with a single image. Deep thought over a brand makes it stay much longer in the heads.
Design of a website needs to be a constant change. Stale website design will not only stop new users from coming in, but it will also drive away existing users. People love consistent changes in their environments. Anything on either side of the scale will irk everyone.