Now, here comes the graphic design part!
A menu of hypertext links works very well. It is easily understood and fulfils the intended function admirably. Everybody knows that a chunk of underlined text is a clickable hyperlink. If you decide that you want to provide an alternative to this tried and tested interface convention, you have to come up with something that works just as well, if not better.
Now, the term 'graphic design' does not always mean the same thing to different people. When I say that I'm a graphic designer, some people stare back blankly and others ask if it something to do with 'commercial art'. Graphic design is about visual communication. That communication can be at an intellectual level or an emotive level – it speaks to the mind and the heart. It has to work at a functional level and an aesthetic level and breaks down into two main areas – 'design', meaning fit for a purpose and 'styling' which is about eye-appeal.
There are designers who deal solely with functionality and some who seem to go the whole hog in the eye-candy department but looks without function or function without looks rarely leads to success. You need some of both.
That is why we tend to shy away from pure text hyperlinks and why we often try to hide the hyperlinks completely. There is not much 'eye-appeal' about a page of plain text with underlines even though it might work perfectly functionally. On the other hand, if you take away the clues that text is clickable, and don't provide a good alternative, you are left with a page that is saying, "No links here, mate. This is all you get!"
A good graphical user interface communicates its purpose right away. You shouldn't have to mouse-over elements to see if they do something or not. If the user has to play 'hunt the thimble', it is an annoying waste of time.
Navigational elements are like road signs. When did you last see a road sign where you had to lift a flap or push a button to see it?
Rather than creating a whole new set of rules from scratch, you can adopt rules that have already been established. That's what you do when you play football, golf or poker. It doesn't make them any less enjoyable. The visual 'metaphor' takes a set of rules from a real life environment and applies them to a computer interface.
When Apple launched the Lisa in 1983, it wasn't the fact that it had a mouse, or pop-down menus and floating windows that was the revolution nor the fancy graphic icons and dialog boxes. Yes, it had the first commercially available Graphical User Interface for an operating system but the real genius was 'the desktop' - an on-screen, virtual reality, completely parallel universe with things that everybody already knew how to use - folders, documents, a drawer with a calculator, note pad, scrap book and a trash can.
The visual metaphor is now the de facto standard for most operating systems and the programs that run within them. It's not the only way, but it does make life easier.