WITHOUT REMORSE is one of my favorite Clancys. I like the personal approach, in comparison with his others, which tend to focus on the action thrills. Our hero stalking the slum jungle, letting nothing stand between him and vengeance against the entire drug community...
But then there is THE HUNT FOR RED OCTOBER, so much more suspenseful even than the suspenseful movie; RED STORM RISING, with its hero conducting gorilla warfare over the bare rocks of Iceland; CLEAR AND PRESENT DANGER, with Jack Ryan conquering at the highest levels by conquering himself; and THE SUM OF ALL FEARS, which is about summed up by its name. In SUM, I think Clancy does an especially good job of showing how out of touch with reality his villains are, and extending it to others with the same mindset.
I can't talk about DEBT OF HONOR or beyond, because I haven't read those later books yet.
Alynna, I recommend shunting these posts over to a Tom Clancy thread.