I feel like saying cardassians also, but I might be influenced by my own taste because their a favorite. But yeah, the casting was great and the stories interesting, lets just say they had ingredients for success.
I liked DS9 so much because they would actually explore races instead of just taking a peak every so often. Don't get me wrong, other shows did great stuff. But I felt like DS9 explored the races more then the other shows, and really got into it.