Best Ad Blocker for Safari.

It's frustrating that Apple won't implement Ad Blocking for Safari even though they add to Safari the ability to block pop up windows. While I don't mind advertisements related to the website I'm visiting it can be annoying not only seeing third party flash animations but also the loud audio sounds some of these advertising designers have implemented (ie: Shoot the duck to win a prize). Anyway, what's the best Ad Blocker plug-in for Safari that's not only free and easy to use but actually works (ie: Allows custom configuration for ads not blocked)? Has anyone noticed any issues running the Ad Blocker they've chosen to install?