Yes, Selleck was the star of the show, but if it weren't for Hillerman, Mosley and Manetti... I don't think the show would have been the same.

The first three seasons of Northern Exposure featured one of the best overall cast of characters in tv history.

Others:

Seinfeld
LA Law
MASH
Cheers
Happy Days
Mary Tyler Moore
Friends
and presently....Deadwood and the Sopranos.

Most of the greatest have already been mentioned.

The big three:

M*A*S*H
Cheers
Seinfeld


I would also put up there Freaks & Geeks(mentioned), Sports Night and Arrested Development. They all have great ensembles and you want to know more about every character, not just one or two of your favorites.

Here are a couple of mine. Several of my other favorites have already been mentioned.

Monty Python's Flying Circus
Batman (1966-68)
Coupling
Barney Miller
Black Adder

Huff: I would've quit watching this show after the first few episodes if not for the amazing cast.

Taxi: Devito, Kaufman, Hirsch, Lloyd. Taxi will probably always be my favorite sitcom.

Newhart: Both shows are classics, but I really have a fondness for the gang at the Stratford Inn.

Trying to keep on naming ones that haven't been mentioned
Roseanne: I think Roseanne's personal life made people forget how great her show was. The kids weren't anything exceptional other than Sarah Gilbert, but Roseanne, John Goodman, Laurie Metcalf, Estelle Parsons, and Shelley Winters were great.

Chicago Hope: Adam Arkin, Mandy Patinkin, Hector Elizondo, and Peter MacNicol. I quit watching after Mandy Patinkin and Peter MacNicol left because they were my favorite characters. The show fell apart just like all David E. Kelley shows do after the first couple seasons. I hope it comes to DVD because I skipped the final season when they later revamped the cast and I missed out on Lauren Holly and Carla Gugino I remember the critics saying the show was good again, but by then it was on the chopping block.

Honorable mention to Wings and Ned & Stacey, and not just because I like Thomas Haden Church. I did like Flying Blind too, though

Wait a second, nobody said Scrubs? Drop Chicago Hope to honorable mention on my list.

I've got to go with the Mary Tyler Moore show. The cast truly gelled to the extent that when Mary gave the "we're family" speech in the final episode, you truly believed it. Additionally, every single top-billed cast member went on to have a successful series after the show, every single one! I can think of no other show where that's the case:

Ed Asner - "Lou"
Cloris Leachman - "Phyllis" (it actually was on for three years)
Valerie Harper - "Rhoda", "Valerie"
Gavin Macleod - "Loveboat"
Ted Knight - "Too Close for Comfort"
Betty White - "Golden Girls"
Georgia Engel - "Coach"
John Amos- Quite a few, most recently "The West Wing"

Several of my favorites have been mentioned. I'd add The Addams Family. Gomez and Morticia really seem to love (and lust after) each other. Rest of the cast is great.

First West Wing cast
Cheers after Coach died
Happy Days w/ either Al or Arnold
Law and Order the version w/ Angie Harmon
90210 after Brenda left and Val joined
the Sopranos after ***** and w/ Furio


currently Deadwood

If Seinfeld and M*A*S*H are not in your Top 5, you need your head checked.

St. Elsewhere
Taxi
The wonder Years (first three seasons)
WKRP
Get Smart

YOu are missing some funny-ass stuff.

MASH
Cheers
Gunsmoke
I Love Lucy
Happy Days

I cant believe only ONE person mentioned THE X FILES!!!!

THE X FILES 4 EVER

Friends, Cold Feet (UK), Coupling (UK), and despite the fact that I personally loathe the show, Seinfeld.

My Top 5 ensembles:

M*A*S*H

Barney Miller

The original "Not Ready for Prime Time Players" (SNL 75-80)

Frasier

Star Trek: TOS


Rounding out the TOP TEN:

Firefly

Coupling (UK)

All in the Family/The Jeffersons

Soap/Benson

The Mary Tyler Moore Show/Rhoda


Honorable Mention:

Alice

Happy Days/Laverne & Shirley

Roseanne

Magnum P.I.

Miami Vice

ER (early seasons)

NYPD Blue (early seasons)

Are You Being Served

Dallas/Knots Landing

The Big Valley

Sitcoms:

M*A*S*H
The Mary Tyler Moore Show
Barney Miller
Cheers

Dramas:

Mission: Impossible
Hill Street Blues
The West Wing
Buffy, the Vampire Slayer

M*A*S*H
Cheers
Taxi
Arrested Development
Seinfeld

Only one vote for Sopranos?

INPO-

Seinfeld
MASH
Andy Griffith
Friends
Sopranos
Gilligan's Island
Fraiser
and too early to really tell but I got to go with Lost

Mission: Impossible
Taxi
Frank's Place
Hill Street Blues
Firefly
Arrested Development

Seinfeld
MASH
Murphy Brown
Friends
NYPD Blue