There was a series about to start on another cable network recently. The series had already aired somewhere else. I went on the net and looked for episode guides, which I found. And sure enough, one of the main characters bites the big one after the first couple of seasons. The actor wanted to go on to other things and the producers didn't want to recast the role. From the descriptions in the episode guides, it was the only character I would have really liked. So I said no thanks, and haven't tuned in.
I guess it's a difference in tastes... I treat a good series like Farscape or Babylon 5 like a novel -- if I really enjoyed it, I'll read it again from time to time. Even when I know the ending and the fates of the characters, I still enjoy revisiting them.