I have been increasingly impressed, over the last couple of years, of the overall utility that WordPress provides for website developers.
When I first started to use it, I only accessed the basic layer of usefulness, and used it as a backend for my blog. But it has proven itself to be robust enough to be easily used as a CMS for individuals and Small/Medium Businesses that want an interactive website but don’t have the time/budget to get something completely custom created for them.
On the other side of the spectrum, as a developer WordPress can also make my job much easier by giving me a framework that already handles all of the basics for a website, and then provides me with the hooks necessary to extend the basic platform and provide specific functionality for my clients.
Along with that extensibility wordpress has a large plugin database where others share their custom creations for anything from publishing a podcast to keeping your visitors up with your tweets. Many of these plugins provide the functionality that my clients are looking for with only a few minor changes to match the clients specifications.
Additionally the power to hook into the wordpress backend and pull out relevent information can help you produce or utilize some existing themes that will make your wordpress install become and amazing dynamic website, not merely a blog.
All that being said, WordPress has become a staple in most of my website development projects. and can greatly enhance your development process, if you are willing to let it.