The word "great" can have a lot of different meanings. However the question "what makes a design great?" can be useful. Here are a variety of sites to consider...
Great Interaction Design
You don't have to know what Fitt's Law or HCI is to appreciate great interaction design. Not flashy, not necessarily pretty, these sites try to do good things for users.
hellocode Very good examples of Flash interaction design and not a bad way to set up a portfolio.
Whichbook.net Computers are logic-based, and so are the controls programmers choose. People searching for books might want a book with a certain feel to it. Enter the affective control and desirability design. Completely befuddles programmers how it works. They can make the controls -- no problem -- they just can not fathom how it does what it does. (Hint: Not bad if you want a barrier to competition.)
Don'tclick.it A mouse based interface with no clicks -- makes you think in a different way.