I like this series of advertisements from Capital Magazine:

Worker+BLK.preview

It’s now or never if you want to invest in real estate.
Before you begin listening ask yourself who’s talking.

Emir+BLK.preview

The electric car has no future.
Before you begin listening ask yourself who’s talking.

Butcher+BLK.preview

Fish are becoming very overpriced.
Before you begin listening ask yourself who’s talking

Here’s the detail on the campaign:

Advertising Agency: Young & Rubicam Paris, France
Creative Director: Les six
Art Director: Sebastien Guinet
Copywriter: Josselin Pacreau
Asst. Art Director: Julien Hérisson
Aired: June 2009

Perhaps we should also have one like this, as students are forever predicting the demise of libraries …

g