First for the geek part; I heard Patrick Stewart in an interview where he said there are a few scenes from the Star Trek TGN pilot where he spoke in a french accent. So awful they are never to see the light of day apparently.
I live just south of Canada and was in Toronto last week. In the movie Miracle Kirt Russell tried way too hard with his Canadian accent. It came and went throughout the movie, but there was one or two scenes that were painful.
Did I say they should be speaking in German accents? [rereads] Nope, didn’t think so. Personally I’d have had them speak in their normal voices (unless Damon wanted to do the “how you like them poisoned apples?” Southie accent again just for absurdism).
And most of his troops didn’t even try to lose it. When Cleitus (played by Liverpudlian Gary Stretch) lectures him about the men wanting to take their loot and quit the campaign it was absolutely painful. I kept expecting him to say “But do they call me “Cleitus, the Babylonian Slayer”? NO! But #$*% just one elephant…”)
I, for one, am glad that they stuck with a British accent. The French accent becomes quite grating after a while.
“Open 'ailing frrrequenzees, Meestaire Hworrf!”
In Sahara, Matthew McConaughey’s character and Steve Zahn’s character are supposed to have grown up together, yet McConaughey sports his Texas twang and Zahn makes no attempt to hide his Minnesota accent.
Where the heck are these guys supposed to have grown up, so that they wound up with two completely different regional accents?
What did you think of Albert Finney’s accent in that film?
Fakey. Not quite as bad as McGregor’s but not good, either.
I liked that movie, but would have enjoyed it much more if the fake accents hadn’t kept jarring me out of the moment.
Do the Trade Federation guys in the Star Wars prequels count?
I think you misspelled “naked.” 
Claven.
He did a nearly passable version, but if he was in a bar in Boston, he’d have been immediately been picked out of the crowd as a “poser.”
Those from the other New England states can get close, but it’s still not quite right. Close enough for mass distribution, but not enough for the regulars.
-Butler
(I can pick out those from slightly north of Boston, Revere to the Peabody/Salem line, from those coming from the city itself, but that’s only because I pay attention, and have lots of family from that slightly north of Boston area.)
The one that bugged me was The Shipping News. I have heard bad Newfie accents before but usually in comedy and I’ll forgive that to an extent. This was an entirely different creature.
This was supposed to be serious, and seeing as they filmed it in Newfoundland and had a few supporting players that were Newfies (like Gordon Pincent) it boggles the mind that all the leads screw up the accent. Dame Judith Dench was atrocious but Moore made me want to stop watching all together. For once I understood how Southerners can get irked by people trying to do their accents.
They mimic a couple of sounds but miss the entire speech pattern and lilt.
[rereads] title “inappropriate fake accents”… “I find this annoying considering that the Brothers Grimm lived in what’s now Germany”… “star tried an accent that not only sounded fake but had nothing to do with the character’s nationality”… okay, if you say so. Personally, I suspect an American and an Australian playing proto-German brothers would’ve been even more off-putting than a fake German accent. At least affected British implies “they’re in Europe.”
Same here. All the accents sounded disconcertingly off to me. Except for Jessica Lange, who sounded authentic; and Helena Bonham-Carter, who didn’t sound authentic but had enough confidence to sound like she knew what she was doing.
Maybe the problem is Kurt Russell was playing Herb Brooks, from Minnesota.
I didn’t actually see Cold Mountain but I saw enough clips of it and I thought that Nicole Kidman sounded like an Aussie trying to do a Southern U.S. accent.
And if you’re going to mention Alexander, where many of the British and Irish actors used their normal accents, then why not mention Angelina Jolie’s accent? She sounded Slavic. Did I miss some explanation in the long, dull expositions where someone might have explained why she spoke that way?
Gerry Adams doesn’t seem to have a really strong Belfast accent though, or at least not the “fingernails down blackboard” accent I associate with the place, being a culchie from an area thats over-run with the bastards every summer…
I think the producers probably decided that a strong Belfast accent would be difficult for American viewers to understand and went with the Generic Northern Ireland accent instead and as I said above I found it surprisingly well done. Which is a rare thing, as you know its usually “Top o’ the mornin’ t’ ya!”, “Begorrah!”, “To be sure, to be sure!”
On the subject of Sean Connery, the only accent he ever speaks in is a Sean Connery accent.
I like how they did the foreign language thing on Hunt For Red October. For the first, oh, 5 or 10 minutes of the movie, you’re following these Russian crewmembers around as they speak Russian with English subtitles. Then it switches from subbed Russian to English in the actors’ native accents… IN THE MIDDLE OF A SENTENCE. 
Re: The Trade Federation’s accents: Sounded like a perfect Trade Federationian accent to me 
This is purely a guess and based totally on your description, as I have had the distinct pleasure of not seeing said film. But since Alexander was a Macedonian, and since Macedonia is one of the segments of erstwhile Yugoslavia, and was such before Tito created Yugoslavia out of all those other countries/areas that went back to being whatever they had been before Tito, I suspect that the notion Jolie or her voice coach or the director must have had was “Hey, let’s go Slavic. Everybody will note the irony.” Maybe they guessed wrong.
Continuing with the theme of inappropriate accents used for comic effect, how can we forget the ‘Pink Panther’ movies wherein Inspector Clouseau speaks with such an exagerated accent that Inspector Dreyfus can’t understand him (I recall a bit about “a beggar and his minkey”).
I never could place Dreyfus’ accent until I just know looked up Herbert Lom on the IMDB and found out he was Czech.
I also seem to remember that in one of the movies, Cato (Burt Kwouk) loses his outrageous accent for a moment and he speaks reasonably unaccented English.
But back to a serious movie, in Usual Suspects the Hungarian gangster speaks Hungarian with an American accent.
Whoops, my bad. (It was still a godawful accent.)
I had the same reaction when I saw Bob Hoskins using his normal speaking voice. I had only ever seen him play Americans.