Skald the Rhymer brought up the question of celebrities in this thread, but said:
So, as a companion piece: which fictional characters would fit in well here… and which wouldn’t?
My nominations for best and worst: Mr. Universe from the Serenity movie and Foul Ole Ron from the Discworld, respectively.
Best:
Greg House
Worse:
Fox Mulder
Horatio Hornblower would probably get along well enough in here, no doubt posting to threads relating to the playing of Whist, drinking of Coffee, and threads of nautical interest, but he’d be wise enough to recognize that he’d never be able to devote the time to reading the SDMB and still be able to perform his duty as a naval officer.
Jeff from Coupling would enjoy posting to the SDMB, much to the continued amusement and dismay of everyone else. He’d probably have some entertaining input on a couple of my threads.
I can see Barney from How I Met Your Mother also posting, with his… unique insights on life.
I thought of Ignatious J Reilly from A Confederacy of Dunces as the worst. He would love opining to the world all at once and might get very sniffy indeed at being challenged over anything.
Not terrribly well put by me - tired.
MiM
Ellie Arroway from Contact would fit in fairly well
Aunt Bea, not so much.
I can see Tim from Spaced fitting in nicely in CS and the Games Room.
I think Atticus Finch would be a valued poster, though not very prolific. Making on point comments and posts in both GD and GQ, but I suspect he’d be a bit of a lurker in the more frivolous fora.
Peter Parker would be an interesting poster, too. But stay out of the crossfire when he and Bruce Banner start to debate rad health physics.
Would Mark Twain post to the SDMB?
I’m sure the comic book guy would fit right in here, somehow you all remind of him 
And I will have to nomiate Zap Brannigan as the antithesis to the SDMB
I think Greg House would have so many Pit threads about him the Mods would have to open a new catagory for them.
I do think Wilson would be a fine addition. And also Wilson from Home Improvement.
I can see Tim from Spaced fitting in nicely in CS and the Games Room.
Now, I thought he’d fit right in.
I’ve said this in book threads before, but Bartimaeus, the 5,000-year-old djinni in Jonathan Stroud’s trilogy would be a great Doper. He’d start the best Pit threads.
On the other hand, I think Dana Scully, FBI special agent and physician, would fit in very well here. She’d have lots of interesting posts on medical and law-enforcement topics, and could join forces with the anti-loon, anti-conspiracy Dopers.
Sherlock Holmes would also have fun, I suspect.
Morgoth and Sauron would just glower at everyone and plot against them.
I can see Willow Rosenberg from Buffy the Vampire Slayer being an excellent addition to this community.
I can imagine several figures from the Bake Street universe having exchanges today:
John_Watson_MD: I am shocked by what I read in this morning’s newspapers about the latest assassination in the Balkans.
Sherlock: Relax, my dear Watson. I think you will find there’s more going on there than you read in the newspapers. I have been engaged by a Russian heiress to solve the mystery, and I expect to have it solved within a week.
Inspector_Lestrade: Cite please? (And that goes to both of you: what newspapers, what assassination, and what heiress?)
I’ve always pictured Slippery Jim Digriz from the Stainless Steel Rat books being an active snarky contributor.
And I’m sure any of Heinlein’s verbose, flirty, cerebral, plunging-necklined women would be most welcomed.
Flann O’Brien’s De Selby would have fun with the “plane on a treadmill " and how to weigh your own” head type of stuff.
Doctor Strangelove. If we’re willing to overlook the…one-handed typing.
Handy for when a serious discussion of hypotheticals comes up, at least—like the ones that start with “How do you kill a…”.
That son of a bitch Nick Van Owen would probably fit in distressingly well, at times.
I’m sure one favorite poster would be HannibaltheCannibal