I ran a bunch of errands today and plowed through the entire audiobook of Freakonomics. I'd say I liked it even more than Blink. It turns just about every issue on its ear with a look at the data surrounding it. Babies, Guns, Schools, Corporations, Crime, Sports, Abortion, Drugs, Cheating, Gangs, Murder... everything gets the treatment. I could immediately tell their approach to answering questions is the type of thing that will make me follow their work for as long as they publish books on the subject. I sincerely hope they've got a whole Freakonomics Series in them.
If I had to point to any problems with the text (and this is a small nitpick that will make me sound like Andy Rooney, but...): I don't like it when books aimed at the mainstream mix and misuse words between the scientific and causal realms. The authors here called every hypothesis a "theory" and when pointing out correlations in their data would often said the data "proved" a point. To "prove" something and describe something as a "theory" are both significant terms used when describing research and while Gladwell does it in Blink a lot too, tenured economics professors should know better than to play loose with meaningful words.
I started in on Sarah Vowell's Assassination Vacation audiobook shortly after Freakonomics and so far it's a wonderful mix of quirky comedy and a history lesson. Also a highly recommended iTunes purchase.