I’ve been using 1Password by Agile Web Solutions for a while now and it is by far the best Mac program I have used to manage website passwords. It integrates with all major browsers using a great autofill feature, eliminating the need for cut-and-paste.
I also use it to securely sync passwords between Macs using Dropbox as well as manage website passwords on my iPhone using their new iPhone App. It also includes features for credit card management, anti-phishing and password generation.
See Previously: 1Password iPhone App, Making Password Synching Easy
UPDATE: It turns out that 1Password is having a 50% off Halloween sale today.