I started using SuperGenPass a few months ago from a recommendation here and have been really happy with it.

http://supergenpass.com/about/

It's a bookmarklet so you can review the code behind it and use it on any computer. You only have to remember your master password and it converts to a new password for each site. Usability-wise it's usually only 1 extra click - you put your master password into the web form's password field and the bookmarklet writes the generated password for that site over it.

I still wouldn't use it for banking or my email, but for most other things it's worked well.