I've recently seen La Vie En Rose, the film of life of Edith Piaf, and was expecting them to have, as seems to be the trend, the actress sing the songs. However, they dusted off audio recordings of Piaf's performances and used them in the film, lip-synced by the fantastic Actress that portrayed her.
Normally, I would have considered this a little of a cop-out, but anyone familiar with Piaf's work would know that no amount of training can get an actress to sound anything close to her power and timbre.
As an example, I've attached the opening 1m42 of the film just to show what I mean:
Click to play the MPEG4 clip
Now, here's the Pugwash review: A little selective and potentially disjointed, but a superb film with an amazing performance by Marion Cotillard (previously seen as the hot girlfriend in Taxi 1-4) and some wonderful direction. If you're not scared of subtitles (or you speak French) then see it. Oh, and seriously, don't try it without subtitles unless you're really up on 20s-60s Parisian argot. From time to time, I was glad to have the subtitles, to be honest, and I'm just back from 8 years in Paris.