I heard this question on a podcast yesterday, and it lead to a fun flight of fancy. I’d choose Sid Ceasar’s show, working with comedy greats like Woody Allen, Carl Reiner, Imogene Coco and dozens of other legends of comedy. Mr. singular chose Ernie Kovacs for the same reason, although we both agreed that, if forced to choose a more contemporary show, it’d be either Deadwood or Arrested Development. Anyway, it’s a fun thought - what’s yours?
Buffy the Vampire Slayer. That way I’d always have work on other Joss projects.
I was thinking the same thing, but more because of the many potential hook up opportunities with my fellow actors :). I guess I’d be satisfied with shows like Charmed, Gossip Girl (I’m not that old, so it’s ok) and Baywatch as well.
Mythbusters. Not only would it be a hell of a lot of fun, you’d occasionally get to see Keri in a bathing suit (and all the time in tight tee shirts and jeans). Win/win! Hell, I’d do it for free, just to get the blow up cars, shoot guns and run around in paper armor, etc etc…
-XT
That’s funny - the podcaster (Adam Carolla) had the same approach - choose the show that promised the best advantage to your career. We just wanted to work with/meet great people. Just curious - are you in any way in show business?
+1
I’d have liked to have been a Vulcan on one of the Star Trek series, or possibly a Klingon.
Or on Xena, you know for the leather gear and whatnot
Or Stargate (SG-1 or Atlantis) for the shooting of aliens and going through a wormhole to another planet
On stage every day.
I teach. 
This is a good question…
One of the ones that would be in my top 3 is definitely “Whose Line is it Anyway”. I love improv comedy and selfishly think I’m really quite good at it, so I think that would have been a lot of fun to do.
Another one would probably be on “Friends”. Always a funny show IMO and a sitcom seems like a fun environment to work.
Lastly would be on “Sports Night”. My favorite show of all time, a chance to work with my idol (Aaron Sorkin) and it would give me an opportunity here and there to excersize my drama muscles.
According to lots of standup comedians, a supporting role on a sitcom is one of the sweetest jobs in showbiz. You’re not needed daily. You roll in, hit your mark, say your lines, and that’s a wrap. So a sitcom, and something long-running (to keep the checks coming) would be my motivation.
Seinfeld (hopefully avoid the curse)
Friends (don’t care for it, but I want the salary)
Simpsons (super long-running voice work = awesome)
Farscape - Just seemed like a fun group of people and it was a great show.
Firefly - Again, great people and a great show.
I’d love to be a judge on Project Runway. This way I’d get to meet Tim Gunn, exchange quips with Michael Kors and watch really talented people up close. Oh and see if the clothing presented really is that bad.
I’m probably aiming low here, but I wouldn’t mind moving onto Wisteria Lane and becoming chummy with the Desperate Housewives. I don’t care what anyone says, I think they are a hoot. I’d have a friendly cohort of funny, loyal, interesting neighbors; I’d be invited to all kinds of parties all the time; my house and yard would always be picturesque and spotless; I would obviously have enough money to sustain the upper middle class lifestyle and wardrobe. There would never be a dull moment, what with the random murder or disappearance. If I was single, there would be a plethora of attractive, available men to choose from. I’d go shopping with the cute funny gay guy, have iced tea on the patio with Bree, be invited to the weekly poker game, and trade sassy gossip with Karen (McKluskey). Some of us don’t yearn for much, an idealized version of real life would suit us fine.
It would have to be Star Trek TOS, as a cast member that also got included in the movies. With residual sydication checks, movies, conventions, stunt casting on other Sci-Fi shows, I’d basically be set.
Real Sex.
Lifestyles of the Rich and Famous. 
Babylon 5 for me. I’d be satisfied with a small, supporting role that got the occasional line to speak.
Oh yes, Firefly!!
Y’know I was thinking the other day how nice it would be to live on Wisteria Lane, people are friends with each other and take an interest in each others lives and when a new person arrives on the Lane, the girls get together to welcome them with a muffin basket…
sigh
I moved into a new house nearly 5 years ago, I still don’t know who my neighbours are… I rarely see them. In fact you hardly see anyone on the street at all.
The A-Team!
I’m stronger than Mr T, prettier than Face, weirder than Murdoc, and I out rank the Colonel.
Breaking Bad – I’ve been listening to the commentaries and it sounds like these folks are having a ball. It also sounds like they have a lot of respect for each other. Crew members get just as much praise from Gilligan as the actors. He especially loves his construction crew.
Current show: Psych!