I have looked at and worked with a LOT of learning management systems over the last few years. Moodle, Bb, WebCT, Sharepoint and more. I have also suggested that sites like Google Maps and Timeglider could be used as LMS tools. I have never found the perfect LMS, but recently I have been playing around with Schoology and I really like what I see. Think Facebook meets LMS.
Easy to use, intuitive, well built, well designed, new, fresh, robust...oh, and FREE! What more could you ask for?