For eight years, every Monday at 9pm on Fox, this was must-watch (in real-time) for me.
Jack Baur is a God among men. 
From the time time Mandy parachuted out the airplane to Chloe telling CTU's monitors to "shut it down" after Jack (The GAWD) said "thanks" I was hooked.
I admit the show slipped after season five's epicness. But, I still looked forward to Jack torturing someone for info, CTU setting up the perimeter, the Bad Guy getting through those perimeters, CTU high-tech electronic gadgets, The CTU mole, the split-screen with the running clock, and Jack ultimately saving the day for the umpteempth time.
President Palmer, Michelle, and Edgar (how sick was the nerve gas murking everyone down at CTU).My Top Five Seasons:
1
5
4
2
7
Silent Clock countdown for one of the GOAT shows of the new millenium.

*goes off to do the exact opposite *
).
good.