Content is king. That’s the time-honored lesson you learn when you study web design and management. So perhaps it isn’t surprising that some of the most hideously designed sites are also the most successful.

For a business site, design does matter because a company’s brand is riding on the user experience. But for other types of sites, ugly just works. When design surpasses content and functionality, the user can feel left out, as if they are not getting the most from their visit. So some sites take advantage of this principle, and thrive on simplicity and lack of design.

So without further ado, here are my choices for the ugliest, yet most successful, websites.

5) Ebay. It’s a miracle that anyone can get anything done on this site. Navigation and content are all over the place, account settings are buried under mountains of navigation menus. Yet ebay remains the category killer for online classifieds.

4) Craigslist. Not to be outdone for simplicity,this classifieds site is the epitome of bare bones. Not a graphic to be found, 100% text, and no frills. But, for millions of users, it gets the job done.

3) Huffington Post. One of the best aggregators of content on the entire world wide web. Also one of the worst designed. It’s like someone threw up on the page. The Drudge Report follows a similar, design-despising structure, but the powerful content keeps users coming back. And the site has undergone some face-lifting lately that give users just enough structure and navigation to balance the eye sore a bit.

2) Amazon. Yes I know I’m an admitted Amazon addict. But the site — come on, big-time atrocious. The product description is found where? Oh, of course, down about 3/4 of the page below all the other items you might want to click on and lose track of your original purchase. And yet it works. How can something so bad be so good?

1) YouTube. This site was born during the dark ages of the Internet and essentially gave birth to video online. Despite an unbelievably bad design and user interface, it rakes in over 3 billion views per day, with 48 hours of video uploaded every minute. Simply staggering, especially considering how difficult it is to do. Again it goes to show how content rules.

So there you have it. For my money, the five best worst websites in the world. I’m sure there are others that are in the same league — so let’s hear it. What are your picks?