I stopped watching after season 2, but I've started watching the latest season from the beginning. It's pretty good, and the plot of each season is largely self-contained, so each one is easy to follow, as long as you don't miss an episode within the season (they move very quickly).
Synopsis: Jack Bauer loves America and won't apologize for that. He'll do whatever it takes to keep you and your smelly hippie ass safe, so quit bitching about him torturing terrorists.
Really, that's a fairly accurate synopsis of the show.
Still, it's quite entertaining and this is a thread to talk about it I guess.