Fans may not have been too happy with the way that 24 ended, but they might've been even less happy with what was originally going to end the series, according to executive producer Howard Gordon: The death of Jack Bauer.
Talking to Assignment X to promote the DVD release of the show's eighth and final season, Gordon said,
I think I maybe even wrote [a death] scene and in the end it felt too depressing. I think it would have been a really depressing moment. I don’t think it would have been surprising, I think it would have been more depressing than surprising. In a strange way, that’s probably the ultimate, tragedy and probably the most politically correct ending, but it wasn’t something anybody wanted to commit to. Not just for the reason of the show, but honestly, if we had really felt that was the best ending, we would have all gone for it... The way it would have been, like any tragedy, the President would intervene. Having stopped her terrible choice to coerce everybody to the Peace table, she would try to save Jack and it would have been too late. Like Romeo and Juliet, it would have been the function of the timing of it.
Of course, keeping Jack alive also makes that movie spin-off more possible...