Probably SSA Aaron Hotchner on, "Criminal Minds." But SSA David Rossi, played by Joe Mantegna (sp?) is very close.
I also like the CA Bureau of Investigation agents on, "The Mentalist." Esp. Agent Cho and the dame, whose name momentarily escapes me. (I need coffee, and am about to make some.) She's the lead agent, who puts up with the hero's mannerisms. Oh: Spcl. Agent Lisbon. And I like van Pelt, who's hot, if you like redheads, which I generally don't. I keep hoping that she and one of the male agents will admit they have the hots for one another.
The least favorite are the black guy (Morgan) on, "Criminal Minds" and the wimpy doc. And the asst. on, "Hawaii Five-O." He's played by James Caan's son. Too short and too New Jersey for my tastes. But the guy who plays Chin and the chick played by the Korean-Canadian girl are good. Aha! Grace Park!
Oh: Lord, I forgot Tom Selleck on, "Blue Bloods!" He'd be my favorite top cop, even if the show is set in NYC, a place that I detest. His ADA daughter is okay, if a little too PC. The younger son, Jamie, is nice, if a bit naive. The smart-alec son played by Wahlberg is too NYC for my taste, but he does like to protect people and catch crooks, even if he is a smarty pants with a Noo Yawk attitude.
If we can extend this to PI's, the Spenser For Hire series was good and very like the books.