I think when it comes to discussions, choosing just any "one" to reflect upon couldn't be justified, since all the discussions were a great way this class used to promote and advance communication skills and social responsibilities amongst all the students as well as the professor. By requiring students to comment with thoughtful college writing posts it bars any possibility of the common one-sentence thoughtless response I have seen in other online classes where the peers are only doing it because they have to for points. But through all the discussion I actually feel all the students are sincerely interested in the discussion and not just doing it because they have to.
I say there is no one "best" discussion topic because for every new discussion topic there is something new I learn that relates to the textbook topic of the week. For students who aren't usually interested in the current events and news it was a great experience to go out there every week and search up a topic that interest me. And the learning does not simply come from reading the article and summarizing it, but mostly from reading the posts and comments other peers has put. Seeing the same topic being analyzed from so many different perspectives of all the students is honestly much more useful than reading and analyzing it yourself, so many negative aspects such as observer's bias are completely barred off when the reader are offered so much different takes on the topic.
Perhaps my favorite aspects of discussions in this class is how beneficial some of the discussions are to your other major assignments. The E-portfolio reflections and feedback discussions really reminded me about the assignment and some of the advices my peers were very helpful when I was making my E-portfolio. And the midterm discussion was very helpful for the final part of the midterm, seeing so many different articles about a same topic and so many different perspectives and takes on it made the final memo much more simple and interesting to write.
Another major factor I liked about the discussions was response process, it greatly promote both communication and responsibility between the students. For student first time taking an online class, they really has to learn to get out of their "bubble" to both accept or constructively critique another's student's idea. And by following the online netiquette the student really have to demonstrate sensitivity and respect not only towards other students, but as regarding to the topic of this discussions. The discussions really improved my communication and acceptance of other people's viewpoint. I certainly have developed in terms of open mindedness in regards to other's value and perspective, and I also got over some of my stubbornness throughout the half-semester with the interactions amongst the discussion board.