I have really enjoyed using the Moodle interface for my university work.  My wife has been using Blackboard for her work with another University.  Just based on our comparison and experience using both, I would say that Moodle is much more superior.  I was surprised to find out that it is offered free.  Maybe someday I will be able to use it to set up my own class instruction.

Moodle.org: open-source community-based tools for learning.