Reason.tv has an interesting video up, where Glenn Greenwald talks about drug decriminalization in Portugal. Glenn works for Salon.com, and recently wrote a paper for the Cato institute titled "Drug Decriminalization in Portugal: Lessons for Creating Fair and Successful Drug Policies".
It has been five years since Portugal decriminalized cannabis. And in that time Portugal found that instead of spending money to lock people up for using cannabis, it was put to better use towards treatment programs, which resulted in lower drug use overall. Which is exactly what they wanted, but were not getting with their previous strategies.