That other thread we have regarding season six in addition to Neo's testimony prompted me to buy all five seasons that are currently on DVD. I too, had never watched the show but I'm hooked now. Just started season three. I've been going through 3-5 episodes a night.
Jack Bauer is one BAMF (bad ass mutha fuc.ka).
And since you have a Mac, you should download
MacTheRipper so you can make 'backup' copies of the DVDs to cherish for years to come.
I'm glad I've watched the show on DVD. The quality is better (unless you have HDTV) but that doesn't stop the annoying commercials from breaking up each engaging episode. Even with DVR, you still have to fast forward through the junky commercials.
Anyway, this show gets my seal of approval.