I'm running a Joomla! site on top of a Wordpress installation and, while I like Joomla!, I almost wish I'd stuck purely with Wordpress. At issue is whether you

I'm running a Joomla! site on top of a Wordpress installation and, while I like Joomla!, I almost wish I'd stuck purely with Wordpress. At issue is whether you need a full-featured CMS with all the bells and whistles (and associated complexity). Some things to consider are how frequently you'll be updating the site, whether their will be multiple contributors and whether you'll need a variety of modes to present content. As trickjarrett notes above, it's difficult to expand, though the flexibility in creating themes and being able to modify the behaviors of existing components by cloning them and changing them is pretty powerful. Wordpress, on the other hand, can be mangled into just about anything you want since there is a massive library of third-party add-ons and, to me, it's a little more pluggable.