Many of these have been mentioned.
NCIS. Mark Harmon as SA Leroy Jethro Gibbs (Gunny USMC, ret.)
Babylon 5. SciFi, but a very well done 5 year story arc. You have to pay attention.
Stargate SG-1.
Any of the older classics. Dick Van Dyke, I love Lucy, Mary Tyler Moore.... You know the ones.
The Unit.
From the era of great television: Emergency and Adam 12. For a little more humerous: Hogan’s Heros and I Dream of Jennie.