It's like slipping into a ratty old robe - worn and frayed, but still comfy and satisfying:
One perimeter set up - fails.
Another mcguffin (the mysterious package in the wall).
Wild-eyed Arabic-quoting "your-family-will-be-notified-of-your-heroic-sacrifice"-jargon-spewing Islamic terrorists (although they're so less interesting than Victor Drazen and his Chechnyans or Vladimir Bierko and his Russians..)
Disgusting torture/assault methods - Jack biting the neck of his captor (should we now call him "Jackula"?), shoulder nerve cluster severed, spinal cord skewered, Muslim traitor's kneecap muscles sliced..
Jack miraculously survives and recovers from his wounds (see previous shoulder nerver cluster sever and flat-lining after spinal cord skewering).
American citizens becoming paranoid.
FBI throwing its weight around.
Chloe getting involved in a hair-brain scheme (she would've fit right in with the Scooby-Doo gang), almost compromising the mission, then all is forgiven as Buchanan gets involved.
Shady, weaselly White House personnel...
Over-their-head CTU managers.
Did I miss anything?