I was having a hell of a time typing Omar. To be honest, I was sure of very little. My typing skills are admittedly somewhat rudimentary. Though you may be right about McNulty's S preference now that I think about it, I can't help but feel he's J. He's definitely focused and decisive, and he clings to his personal project with Stringer literally for years. He's certainly very inflexible.
This show kicks major ass. I definitely identified with Stringer. I'm tempted to say that Omar is an ISTP. Generally, when I can't figure out if they are I/E S/N T/F or P/J, there's like a 90% chance that they are ISTP.
"You will always be fond of me. I represent to you all the sins you never had the courage to commit."
Reason is, and ought only to be the slave of the passions, and can never pretend to any other office
than to serve and obey them. - David Hume