This one is good to listen in the car, when you just need some background noise. It covers a bunch of Jargon from different professions that could help you at one point. It also explains how to get to the root of a word so you can learn new words on the spot.
It's worth renting
This may be better in book form rather than CD format. The "roots" section was endless to listen to and I found the "jargon" section rather useless. I just did not feel that it was helpful in brushing up or expanding my vocabulary. I would recommend "Word Smart, Building a More Educated Vocabulary".
The audiobook might be able to assist with pronunciation, but I do not feel it will help elevate an average vocabulary to the next level.