I was just getting into "Prison Break" & if I'm not mistaken, I think 24 has just taken "Prison Break's" time slot on TV. As I live in the UK I have to watch new US shows/seasons via torrents, but 24's a good show also, so I'll have to wait for the conclusion of "PB" & Watch 24 instead.
It is the best show on TV. Better storyline and acting than any show currently on TV. They are willing to do things that you really don't expect them to.
In Season 3 when Jack killed Chapelle I was really shocked. I honestly did not think they would go through with it.