Honestly not sure if "detective" is meant as the profession or as heroic-whodunnit-solver. So forgive me if I go with my fave most beloved best profiler, technically.
13 Great TV Detectives
1. Detective Olivia Benson, Law & Order SVU
2. Lieutenant Columbo, Columbo
3. Frank Pembleton, Homcide: Life on the Street
4. Jessica Fletcher, Murder, She Wrote
5. Detective Lenny Briscoe, Law and Order
6. Adrian Monk, Monk
7. Eddie Fitzgerald, Cracker
13 Great TV Detectives
1. Detective Olivia Benson, Law & Order SVU
2. Lieutenant Columbo, Columbo
3. Frank Pembleton, Homcide: Life on the Street
4. Jessica Fletcher, Murder, She Wrote
5. Detective Lenny Briscoe, Law and Order
6. Adrian Monk, Monk
7. Eddie Fitzgerald, Cracker