I’ve been using WordPress for about, say, 5 years now. I started off with Greymatter, tried b2, and eventually transferred to WordPress when b2 disappeared. I remember trying to learn how to use the WordPress theme system back then (WordPress 1.2, anyone?). It was really simple, those times.
The WordPress theme structure is much more complex but efficient now. The downside is, people who have no HTML experience need to jump over a lot of hurdles to understand the whole system. Good thing there The Best Free WordPress Themes For Download out on the web, where people can easily find a theme to suit their needs.
Diventare currently uses a free WordPress theme, mainly because I have no time to actually create a theme of my own. Maybe someday, I’ll end up making something for the site.