Hey, how about George Kennedy in Cool Hand Luke? I still can’t believe he got an Oscar for this painfully bad fake accent.
All of the secondary characters in Midnight in the Garden of Good and Evil
That would be All My Children. Opal was the mother of Jenny, played by Kim Delaney now of NYPD Blue fame. Amazing how much useless knowledge you store up over the years huh? 
I found Russell Crowe’s wife in The Insider absolutely unbearable to listen to. Can’t really speak for whether or not her accent was authentic or not, though, since I’m not really familiar with upper-class versions of Southern accents. (And if her accent was authentic, then I don’t want to be familiar with them!)
Julia Roberts in Steel Magnolias.
There was a piece on this very topic on NPR’s “This American Life” on Friday evening, and the author’s contention was that Robert DeNiro in Cape Fear was the absolute pits.
Forgot to say: I know Julia Roberts is from Georgia, but she went to a speech coach to pick up that awful accent in place of her own natural one, which apparently wasn’t drawling enough for Hollywood (according to the “This American Life” guy).
How 'bout Jody Foster in [i} Maverick*? The whole movie was pretty much a stinker, but that chicken-fried accent she put on was the worst!!
JosephFinn: I’m pretty certain Christopher Guest isn’t British, though he does have a barony.
As far as the OP goes, I suffered through The legend of Bagger Vance this weekend, and while Charlize Theron’s Southern accent wasn’t the worst part of the movie*, it sure as hell wasn’t very good.
[sub]*An honor which is shared jointly by the shallow narrative, the tepid script, and the nonexistent characterizations.[/sub]
oh my God, yes!! Dan Akroyd stunk up that movie something fierce.
I’d have to agree. I saw this movie and I laughed my ass off at Dennis Quaid’s pathetic attempt to sound like a Louisiana dude.
That movie did feature a rather bizarre array of accents, but Olympia Dukakis’ was by far the worst. It was so bad it was just strange. It may have been the worst fake accent of any kind I have ever heard, ever.
puut the buuun-nee daown. (put the bunny down)
[hijack] The accents in The Big Easy may have been awful, but that one sex scene–yikes! Whoo, baby![/hijack]
Hey! When was this? The show I heard Sunday was on the Media Fringe.
He stunk it up enough to receive an Oscar nomination for Best Supporting Actor…
The absolute worst southern accent I have ever heard was from Kim Bassinger in ‘Ready to Wear’.[sub]Ironically, I hear she is from Georgia![/sub]
Nastassia Kinsky in “Paris, Texas”
Michael Caine in “Hurry Sundown”
Laurence Olivier, as Big Daddy in a TV production of “Cat on a Hot Tin Roof”
Christopher Guest was born in the U.S. to British parents. I believed he’s never lived in the U.K. I just watched Spinal Tap again recently, and it was obvious that Harry Shearer was having trouble keeping his British accent consistent. The other actors did a pretty good job with the accents, it seemed to me.
I didn’t see Maverick, but I thought Jody did a pretty good southern accent in Silence of the Lambs.
And about Kim Basinger: Her accent is as authentic as they come. She is from Athens, GA, and her accent comes through loud and clear in interviews.
I didn’t see Steel Magnolias, so I can’t comment on the accents there, but as you noted, Julia Roberts is from Smyrna, GA, so I would be disappointed if she turned in a bad accent.
Dan Akroyd got an Oscar nomination for that abomination of a fake accent? Why do they keep rewarding these horrible accents? First George Kennedy and now this!
Oh yeah, I forgot that Vivian Leigh reprised her horrible fake accent in Streetcar Named Desire. Yech!
By the way, I have some respect for Clark Gable. He was asked to do a southern accent in GWTW, but refused, knowing it wouldn’t have been good. Thank you Mr. Gable.
Speaking of Steel Magnolias, I hate it when directors lump all accents together as if “Southern” were a single type of speech. Kim Basinger does not sound like Dolly Parton any more than Joe Pesci sounds like Rodney Dangerfield, even though they’re both “New York.”
Y’all beat me to Julia Roberts in Steel Magnolias. Ironic, no?
Also, for male I have to also second Kevin Costner in JFK.