Another question that will bring a bunch of different input.
It really all depends on what you are trying to accomplish.
Wordpress was originally designed for a blogging system, and even though it has grown since those early days, at its root it is still a blogging platform. Now with all the available plugins it has been developed into a full fledged Content Management System (CMS) but it does have a rather high learning curve in my opinion.
Drupal has a much more complicated server side, in my opinion. I am pretty certain I will get beat up for that statement, but I think it is true. Also Drupal does not have near the community that supports it.
There is much more available for Wordpress both in support and in plugins.
If I had to choose from those two, I would choose Wordpress.
Have you considered other CMS Frameworks? Again allot of it depends on what your final intention is with the CMS. There are quite a few good frameworks out there that support CMS.
Also make certain that when you make your decision that your Hosting Provider supports the database that your CMS system will require. I have seen that bite quite a few people.
Hope this helps,
Mike