During an interview in support of the premiere of Dr. Strangelove, an unheard interviewer expresses surprise at Peter Sellers' use of an American accent and asks him to use an English one. Here's a video of Sellers trying to find an accent to the interviewer's liking:
What is that, nine different completely plausible accents in 45 seconds? I love actors who can do accents well. Sellers is my favorite, but I also like Aussie Rachel Griffiths playing Californian Brenda in Six Feet Under and Brits Idris Elba & Dominic West (drug dealer Stringer Bell and officer Jimmy McNulty on The Wire). American actors often seem to have problems doing accents although Gwyneth Paltrow does a nice posh Londoner. We saw The Departed this weekend (really good, BTW), which takes place in Boston, always an accent minefield for actors. Locally grown Mark Wahlberg and Matt Damon acquitted themselves quite well. The rest? Not so much. DiCaprio was alright, but the rest of the cast was tuning in and out like an old AM radio.