Drupal, WordPress, or Joomla? (A Trick Question)
I have never personally used WordPress. I read a comparison of it and Drupal some years ago, and knew even then that WordPress would just never cut it. And I've never looked back.
Now if Joomla had been part of the original question, I would have had slightly more qualifications to answer. I used that once (back when it was Mambo, and for all of three weeks), and was sorely impressed at first. But the glow faded quickly when I realized that though it was slick out of the box, it required more work tearing it down to make it do what I wanted than Drupal's simple building blocks offer. And again, I've never looked back.
However, that's coming from a decade of experience on the web beforehand. I really have no idea if Drupal is suitable for someone just starting out. (That is more generic: the author of the original question is a seasoned developer, and specifically to them I say use Drupal, what are you waiting for?)
I dug up a few comparisons from Google, and they seem reasonable (for someone who doesn't know spit about WordPress). 10 Reasons to Use Drupal has an obvious Drupal bias. WordPress Vs Drupal Vs Expression Engine has a WordPress bias. And WordPress vs Drupal can't make up its mind (its author continues to use both).
I found a few comparisons of Joomla and Drupal, but they're largely out-dated, the first on the list dating from Drupal 4.7. Most of the negative points on Drupal on their list have turned into strong positives since then. That was a thorough comparison, but needs to be revised to warrant its current Google ranking.
From a blog, to a news mogul, to a store-front, to a social network, to a university's portal site, Drupal can handle any of it. Just take a look at this slideshow:
With a strong community of developers, there are easy-to-use tools that can handle pretty much anything you can think of. Its underlying architecture is scalable, its API is robust, and Google loves Drupal; its SEO friendliness is well-known. (Although to be fair, as pointed out on Joomla's forums, they're all SEO friendly, and Wordpress does that out of the box, as opposed to needing to install Pathauto for search-engine-friendly URLs in Drupal.)
The rest of this is largely opinion. Please do the research yourself before coming back and telling me this other can do this or that. Without doing a thorough examination of the CMS options, it doesn't do any of them justice to oversimplify their offerings.
Basically, from my perspective, I'd say, if you are an experienced developer, particularly if you have any programming background at all, you need Drupal. If you are looking to hire a developer for your site, whatever site that might be, you need Drupal. If you are a newbie and want nothing more than a blog, then WordPress might be for you.
However, if you're willing to jump through the hurdle of learning the administrative back-end, then Drupal would likely serve you better in the long run. Particularly if you think you might want things like easy video embedding or customizable content entry. And if you want a blog with multiple authors, or forums, or e-commerce (before you ask, I suggest Ubercart, and that comes from having used both that and e-Commerce, but read Diving into Drupal E-Commerce: An Ubercart vs. E-commerce Comparison first), or any kind of social network, then Drupal hands down is the one for you.
If you want some of that, and want it now, and don't want the hassle of learning, and don't care if it's impossible to change it later, then maybe you should stick with Joomla.
Take your pick.