WordPress is a state-of-the-art semantic personal publishing platform with a focus on aesthetics, web standards, and usability. What a mouthful. WordPress is both free and priceless at the same time.
More simply, WordPress is what you use when you want to work with your blogging software, not fight it. http://wordpress.org/
The fact that you are reading this post right now is enough of a testament to the power of the blogging revolution. Even though I am a web designer and and have the ability to design and code my own websites with the assistance of fancy tools to make the job easier for me I have still chosen to use WordPress for my personal and professional publishing purposes.