PHP-Nuke is like windows, it has a large following and is therefore popular, but is actually poorly written and has many security holes. Don't even think about trying to run a HTML validator against it because you will be overwhelmed with errors. I've used it and wouldn't recommend it, you are not missing anything. Yes WordPress started as a blogging system, but has become much more now that they have introduced widgets. I am currently using it and am pretty happy with it. I have used Drupal in the past as well, but couldn't get comfortable with the way the code was laid out when I wanted to do my own modules. But that is just a personal issue, nothing to do with the product, it is good as well.
The nice thing about these are that you don't need to know PHP to start using them, in fact, most hosting services these days offer fantastico that will automatically install it and configure the databases for you. You only need PHP skills when you want to write your own modules/plugins. I started using Nuke before I knew PHP and module just find a module that was similar and hack it up. After a few modules, I was pretty comfortable with PHP.
And yes, to each his own. The biggest challenge for someone starting out is to understand what their options are. Unfortunately there are a lot of commercial WYSIWYG webpage builders with lots of $$$$ for advertising and not much advertising for CMSs because most of them are opensource. If anyone is interested in trying a CMS and needs some help, just let me know.