All the Friend's characters were great, but I never quite found Phoebe to be as funny. I feel her character relied to much on how "odd" she was to be funny. Not the actresses fault, it's the producers/script writers, she could have been a lot funnier if her quirkiness was a lot more subtle. While the other characters were often built on stereotypes, they still had some realness about them - where as Phoebe was just a caricature.
The best is Rachel, hands down ! Jennifer Aniston had the role perfected. At first, the role was just a typical "spoilt rich girl" stereotype, but Jen really developed the role. By the final series, all the other characters still relied on their stereotypes. Phoebe was the oddity, Monica was the bossy/obsessive one, Joey the womanizer, Ross the geek and Chandler was the "funny man", but Rachel was just naturally funny.
