Of the ones you list, I believe Expression Engine is perhaps the most flexible and powerful, if your goal is to build a highly-customized application. On the other hand, Drupal offers the most in terms of contributed code.
But since the question is "What is my CMS of choice?" I have worked with just about every CMS out there, and I can say with great confidence that the best one I've worked with ... is Silverstripe. It has the simplest user interface out there -- simpler than even Wordpress. And under the hood, it's all object-oriented MVC framework, somewhat like Expressionengine. Finally, it has one of the most stellar contributors out there; dude's handle is Uncle Cheese and the extensions he makes for that CMS are just mind-boggling.
The only problem with Silverstripe is that no one knows how freaking incredible it is. It's a complete unknown ... hence it doesn't have the same kind of rapid release cycles, patch fixes, etc. But if people knew about it and knew it's potential, I have no doubt it could take over and render most other CMS's obsolete. It just simply covers all ground, and in my book, could be the definitive CMS for all purposes and levels; from beginner to enterprise.