I use all three of these. I find it easiest and fastest to build a comprehensive and dynamic site with Joomla (especially 2.5 which is a vast improvement over 1.5) whereas I use WP less frequently simply because it’s a blog platform primarily and requires so much customization to turn it into what Joomla does out of the box. Still, when I need to do a blog or smaller, personal site, it’s what I turn to (if not just designing and developing from scratch.)
I started using Drupal because I HAD to due to a client’s requirement (the site was hosted on a university system which used Drupal 6.) So if I wanted to do the work, I had to do it within the Drupal framework. Although I learned a lot about it and can state it is extremely powerful it’s still very complicated and time-consuming to learn and I would not recommend it over Joomla 2.5 unless one had some VERY customized views and tables to create. For that kind of thing, it is absolutely the best. But just figuring out which modules to install to get the features you need can take tons of time.
Actually, I really miss Adobe Dreamweaver Developer Toolbox which only works with CS4 and earlier and is no longer supported by Adobe. I have been able to make a very good living developing database-driven reporting systems with it since 2005.
That’s my 2 cents. Hope it’s helpful to somebody.