What is a well-designed website?
This is a question I have been mulling over for a while now and some ideas have begun to coalesce. When you use the word design there is usually an automatic connection to the look and feel of a thing and this hold true especially for the term web design. "Web design" usually equates to: production of graphical elements, layout/placement of graphics plus textual elements, colour choice, typeface choice. To this end, Joshua David McClurg-Genevese has written an excellent article in Digital Web magazine of the principles of design. This is definitely a must-read primer for those who wish to get a basic overview of the visual design process.

But I believe that the design of a website goes beyond the visual medium deeper into the realm of the user experience. I'm mindful of the praise heaped on the design of Apple products - they're minimalistic and elegant; and on the Mac OS X platform. The refrain you hear over and over again on the Mac OS X operating system is "it gets out of your way and lets you do your job". If you've worked with OS X you know what they mean.

So web design then, encompasses both the visual and the visceral. Going back to the question of the well-designed website, I believe that good design should not distract you from the job at hand, whatever that job might be. In relation to the web, good design should not distract the user from their goal: getting the content.

The user experience is more than the visual experience. It's also the deeper experience which is derived from the implicit website, the structure, which should allow the user not to have to think about how to conduct their tasks. These are Information Architecture principles encompassed by the elements of user experience design. (See also: Don't Make Me Think by Steve Krug) A popular best example of this being the interface to the Google search engine. No thinking needed here, just type what you're looking for and hit search.
I believe, therefore, that good design should be invisible to the user. A well-designed website should evoke a feeling of comfort to the user because the user will be able to perform their tasks easily and quickly, with no hesitation, no anxiety, no frustration in a pleasant user environment. The user environment being the environment within which the tasks are done. It is pleasant when it does not intrude into the user's focus by, for example, a distracting colour scheme, or jarring use of typography, or badly placed elements, or unexpected behaviour, unfamiliar jargon, or unintuitive structure.