Right now, it's between Drupal, Wordpress, and Moodle. I am leaning towards Drupal.
I am trying to build something like an LMS. Users will subscribe to the service, pay a monthly fee, and help themselves to any course. Course resources may include: text, screencasts, flashcards, exams, forums.
The reason I am leaning towards Drupal is: I think ubercart may be better for a paid subscription.