If you are looking for ad blocking, the best method I've found if you're using windows is a hosts file. Completely prevents any tcpip connections to a ton of ad networks and a ton of other stuff you wouldn't want to connect to. So you don't need a browser-specific solution.
It's really easy to install (it's just a text file)
Given that I do a lot of web development, the Firebug debug/development tool is crucial. There is nothing like that on Chrome just yet (that I am aware of). This is the beauty of the Firefox plugin system.