Any other Trek show and I could easily choose. Yet it's impossible for me to do for DS9 because the characters are so enmeshed with one another. Each one is great because of their connections to the others. It's like a domino effect of awesomeness.
It always amazed me how well DS9 could develop both a full complement of main characters (well, maybe except for Jadzia) in addition to a whole host of secondary characters while other shows didn't even seem to flesh out their senior staff.