C'mon, admit it, you watched 21 Jumpstreet as a kid, too, didn't you? I remember spending an entire summer in junior high school watching this show. (The few times I've tried to watch it since have made me cringe, but still.) Love, seriously.
Also, Homicide: Life on the Streets, which is about as far away from 21 Jumpstreet as a cop show can be, fer sure. H:LotS is quite possibly the best television show to every grace the airwaves. But it wasn't fun, you know? It was deep and thinky and sometimes made me scream, but it very rarely had me screaming with laughter.
Other cop shows I have loved? Well, I guess The Sentinel technically counts as a cop show, as does Forever Knight. I mean, the main characters were cops, even if they were also supernatural. Sentinel was cool. I liked it although, again, going back and watching episodes now kinda makes me cringe (but not as much as 21 Jumpstreet, hahahhaha). I like Blair. And stuff. And Forever Knight had angsty vampires! How can you not love that?
I have a fondness for Law & Order, too, of course. Brisco was always my favorite, and the Law & Order/Homicide crossover eps filled me with GLEE because of the combination of Brisco and Munch snark. So of course I like Law & Order: Special Victims Unit, too, because there can never be enough Munch.
Due South. If I could only ever watch one television show of repeats for the rest of my life, it would be a tough call between Star Trek: The Next Generation and Due South (although ST:TNG would probably win because there are just more episodes). DS is the one fandom where I have been really, truly actively involved in the fandom on more than just a reading level (well, okay, I guess I can say that about Highlander and Hercules/Xena fandoms, too, but whatever). Due South is a cop show of extreme coolness and is probably my favorite cop show, even though Homicide is better and 21 Jumpstreet is crackier and Forever Knight and The Sentinel are more sci-fi. I mean, really, what can top a Mountie with a deaf half-wolf in Chicago? With multiple Rays? Nothing, that's what.
There have been other cop shows and pseudo cop shows (like, for example, Kindred: The Embraced, which is only a cop show in that two of the characters were cops) that I have enjoyed, but have never been fannish about or have never seen enough of the canon for to know more (this category includes things like CSI and Starsky and Hutch), and I'm sure there will be more in the future.
But. 21 Jumpstreet. DUUUUUUUUUUUDE. *giggles helplessly*
ETA: HAHAHAHA, my first post of the new year and it's about this! OMG, I am so lame!