If when you're talking designing websites at a more fundamental level, i.e. HTML CSS and JavaScript read this post. Before WordPress there was Joomla. The best website builder program is self-hosted WordPress and here's why.

Reasons why WordPress is the best website builder program

1. WordPress is 'open source' so it has possibly the largest number of developers contributing compared to other CMS (Content Management System) gtechnologies.
2. WordPress has more plugins than any other CMS currently on the market.
3. WordPress has more plugins than any other CMS. Here are some free plugins and some plugins that cost.
4. WordPress has more themes than other CMS technologies.
5. Because WordPress is so popular right now, most technologies make it a point to produce WorodPress compatible products while sometimes disregarding other CMS technologies.
6. WordPress is the easiest CMS to use when considering the amount of options it offers. Tumblr is easier to use than WordPress if you are looking to create a blog to socialize with or post porn.