I disagree about Gilmore Girls. I love snappy dialogue, even though there's no way anyone talks like that. When it's quick and creative, I'm all over it. Liked Dawson's Creek for the same reason. It's the way people wished they talked. :P

The Sorkin hallway-banter-style just wears on me after a while. But the first show I thought of on topic in a good way was Moonlighting.

I loved ER in general, but one thing that always bugged me about "busy" ensemble shows is when the conversations end neatly as the camera smoothly pans from one group to another. It's just a continuous stream of neat little tied bows in an otherwise chaotic setting.

The Unit for Mamet. Justified for every bit of dialogue, it's brilliant. Trailer Park Boys for the art of swearing and shit-isms. Homicide Life on the Street for the interrogations and banter. Seinfeld/CYE for the obvious.

Seinfeld/CYE - Enjoy the continually condescending tone of both of them
Sorkin - Reminds me a lot of the time of old screw ball comedies but more on topic
The Thicke of It - Similar to Sorkin for me, yet doesn't quite hit the "screw ball comedy" bit despite being comedy
It's Alway Sunny in Philadelphia - That snarky, asshole-ish, aggressively loud shit they call dialog, love it.
Taco on the League - Random bursts of brilliant stupidity

Moonlighting - the winner & still champion

Most of my favorites seem to have been mentioned.

Friday Night Lights -- I think the improv made the young actors seem more real, and it really made coach and wife dialog stand out.

Sorkin -- Love the fast and overlapping patter on West Wing. I even like the pontificating on Newsroom.

The Unit -- I agree, the dialog was just enough, and the brevity added to the tension.

Bunheads -- Smart and funny.

Hart of Dixie -- I like Rachel Bilson's clueless sexiness, which comes out in her dialog.

One no one has mentioned yet:

Fringe -- Walter's dialog especially is spot on for a wacko genius.

However, one show where I particularly HATE the dialog is Touch. The constant begging his son to do something the son doesn't want to do really grates on me. I think a great drinking game would be to take a shot every time Kiefer Sutherland says "Jake."

I'm very surprised no one has mentioned Arrested Development in this thread.

Great dialogue, and it took chances too like the iambic pentameter in the Taming of the Shrew episode.

I don't think most of what is being talked about here is a style of dialogue.

That said, the differences in the Newsradio execution and the execution of the league of ripoffs NBC made (Suddenly Veronica's Welcome to Susan) are like night and day. The only workplace comedy that came between Newsradio and The Office that was worth a damn I'm pretty sure was Just Shoot Me, and I seem to recall the creators of Newsradio (Simms) and Just Shoot Me (Levitan) both came up on Larry Sanders.