A good thread focuses on new ideas (make sure to have facts to back it up or at least logic) or interesting topics that aren't repeatedly discussed. While at the same time respecting other's personal views or life. Stick away from discussing topics about gender, race, religion, ethics, etc. Also, creating vs threads usually end up on the hottest thread, but tend to not benefit anyone. Most vs threads end as a flame or troll thread.
The threads I like most are those which are funny; I personally like reading funny threads to get away from all the serious or boring topics.