Another postive vote for Peter Sellers’ American accent – although I’m thinking of I Love You, Alice B. Toklas.
Absolutely every cast member of Fargo sucked the big schwanz in my most humble opinion.
REALLY BAD
Sir John Gielgud as Texan televangelist Clyde Ormiston in Invitation to the Wedding
Tommy Lee Jones in JFK (that is NOT a New Orleans accent- it’s just standard issue Tommy Lee Jones with a gay chaser)
Kevin Costner in Robin Hood (which has been mentioned several times already but can never be mentioned enough)
Richard Dreyfuss in Prisoner of Honor - you’re playing a 19th century French colonel- why are you faking a British accent?
Patrick Stewart in STAR TREK- you’re playing a 25th century Frenchman- why are you using a British accent?
William Daniels (of 1776 and ST ELSEWHERE fame) as Heinrich Himmel in SOAP- the character is supposed to be a stock Nazi accent joke but Daniels couldn’t get it.
Sean Connery in HIGHLANDER (why did the only “true Scotsman” in the cast play a Spaniard?) and HUNT FOR RED OCTOBER (“Aye, I’m changin’ my kilt and my allegiance in some order- tovarish, don’t ya know?”)
REALLY GOOD
Eamonn Walker as Kareem Said on OZ. He’s so convincing as the American urban black Muslim religious leader that I had no idea he was British until seeing him on an interview.
Robert Duvall in THE APOSTLE and in A FAMILY THING (same basic accent)- I grew up in rural Alabama and he could have been any one of a dozen of my neighbors/uncles- it wasn’t just the standar issue Hollywood Southern Accent that’s generally slapped onto any character whether they live in a trailer park or sip juleps on a veranda (really bad offender: the movie MIDNIGHT IN THE GARDEN OF GOOD AND EVIL).
Robert Duvall in THE CAPTURE OF ADOLF EICHMANN- he doesn’t settle for a little theater generic issue German accent but sounds convincing, even adding slight South American influences.
Mike Myers in STUDIO 54 as the nasal coked up gay Jewish businessman Steve Rubell.
Martin Landau as Bela Lugosi in ED WOOD- beautiful job at a complex accent. (Irritatingly, Bela Lugosi Jr. has panned Landau’s performance and characterization since before the movie premiered… even though HE HAS NEVER SEEN IT!)
Excellent: Bob Hoskins as an American
Tracy Ullman as a Baltimorean
Ken Branagh as a Georgian (USA)
Not: Robert DeNiro as a Southerner
in fact any Yankee as a Southerner
Michael Caine was on Conan recently and because he does an American accent in his latest film Conan asked what were some examples of an American doing a bad British voice. Caine was very polite and said, “Well, I don’t want to name names but there was this chimney-sweep character…”
I’ve read that Tom Cruise basically sounded like a cartoon leprechaun in Far & Away.
Always wondered if Kevin Kline was as good at accents as he seems to be. Anyone know if his South African was right in Biko or his French in French Kiss?
All these suggestions are small potatoes next to David Boreanaz’s Irish “accent” on both Buffy the Vampire Slayer and Angel. Look on his works, ye mighty, and despair.
Continuing with the Joss references, I think that Spike (William Marsters) blows the big one with his accent. At least he’s consistent, though - he doesn’t slide in and out like Boreanaz. But when you compare Giles’ accent to Spike’s, you can really hear the difference - Spike uses more consistent stereotypical Britishisms (especially ‘bloody hell’ and the like) in one scene than Giles does in an episode - and Giles (Anthony Stewart Head) just oozes Brit in his mannerisms as well as his speech, unlike Spike.
(Of course, Giles is actually British, unlike SoCal Surfer Boy Marsters.)
OTOH, Drusilla (Juliet Landau) does a stunning accent IMO.
And Wesley’s accent is quite nice as well, although Alexis Denisof, while Seattle born, was raised in England IIRC.
KTM
matt damon in good will hunting.
dude! your from newton, you should know that no one in boston actually sounds like that. what the hell
Orginally in Gladiator they had Russell Crowe doing a Spanish accent. They said he sounded like Speedy Gonezles from Looney Tunes. I think I would have had more fun at that movie. (though god knows why anyone would have a Spanish accent at that period of time)
Cary Elwes (Men in Tights, Liar Liar, Princess Bride) has a good American accent.
Of course, an accent that sounds perfectly correct to some will sound wrong to others. My theater company is directed by an octogenarian British grand damme (and retired English professor) who insists on giving a short welcome speech to the audience before every performance. A reviewer once attended a show and gave us fairly high marks, except for “that woman who came out at the beginning and spoke with that horribly fake English accent.”
We laughed long and loud over that one.
To swing it back on topic, Renee Zellweger (sp?) worked for a couple of months in a shot in London before they started filming Bridget Jones’ Diary. No one at the shop had any idea that she wasn’t a native Londoner.
And I head about (though I didn’t see) a program in which a reporter asked various people in Dublin to critique American actors’ attempts at Irish accents. From what I was told, they completely panned Richard Gere in The Jackal, but thought that Brad Pitt in The Devil’s Own was genuinely from Belfast.
Most Austrailians can do good American accents because their pronunciation of words is only slightly stronger than a thick New England accent. They drop their r’s and lengthen their o’s just like someone from the wilds of Maine.
Having said that, the worst accents I have ever heard were Sean Connery’s accent when he spoke Russian in The Hunt for Red October, Gene Hackman’s Polish accent in A Bridge too Far, and Julia Roberts’ and Tom Cruise’s Irish accents in Mary Reilly and Far and Away, respectively.
One of the best actors for accents is, without a doubt, Bob Hoskins. He is a natural Cockney, I believe, but when I saw Who Framed Roger Rabbit? I swore he was from Flatbush.
Gary Oldman is another one for excellent accents.
Emma Thompson chews scenery like a jackal after a bucket of KFC as the angel in ANGELS IN AMERICA, but she was so good as the homeless woman and the nurse in the same show that I didn’t recognize her. She was hysterical as herself on an episode of ELLEN in which she is “outed” as a native of Dayton.
Meryl Streep: I’ve never understood why her accents are praised. They all sound sort of “from somewhere other than here” the same to me.
Speaking of BUFFY, James “Spike” Marsters actually modelled his character’s lower class Brit accent on Tony Stewart Head’s “real” voice; Head’s upper crust British accent is as fake as Spike’s.
I’m from New Zealand, so am a long way from being an authority, but I thought Minnie Driver did a pretty good New York accent in the movie Sleepers.
Excellent:
Renee Zelwegger in Bridget Jones Diary. I thought she as English until I found out more about her as an actress.
Gwynith Paltrow in Sliding Doors. Again, I thought she was English initially.
To my (English) ears, the best English accents from American actors are from the cast of This Is Spinal Tap.
Worst by far has to be Meryl Streep trying to be aussie in a Cry in The Dark. It was torturous.
I doubt I was alone in hoping the next dingo would take out her voice box.
Seems that the aussie accent range is easier to drop than pick up.
Because by the 25th century, France will have been reduced to the status of “just another British colony” for some 200 or more years. See Futurama for references.
In the spirit of Bob Hoskins (whose nomination I agree with completely), I give you John Mahoney, who plays Martin Crane on Frasier. I was floored when I found out he was actually English.
Accents from the Republic of Ireland don’t seem as bad to me, but when American’s try to play people from Belfast it really seems to show up badly 
How 'bout Keanu Reeves woeful attempt at an acccent in either Dracula or Much Ado about Nothing?
Almost the entire cast either “Xena” or “Hercules” was from New Zealand - it was only rarely audible.