WordPress - My current website (www.totemangel.com) is built on top of WordPress. It is easier to use than the others, but there is definitely a learning curve. It sucks particularly when you want to integrate a shopping cart. I use WP e-Commerce but it is still a royal pain to get them both working together and looking good. Drupal - My previous work is built on Drupal. It is arguably more powerful, but it is too advanced for most people. Most of their available themes suck. If you care more about working well than looking good, use Drupal. Concrete5 - The company I work for uses C5 for its website backbone (www.geomagic.com). Concrete5 is modular, and it is quite a good choice for a website but not so much for a blog. Its built-in forum sucks, and its built-in everything sucks. It is also less popular so it has less community support.
