I use:
MSE
NoScript
Ghostery (stops those nasty tracking cookies)
Various other privacy extensions (betterprivacy, httpseverywhere, etc)
I actually didn't have a problem with Norton. On the one hand it was bloated, but on the other it was absolutely amazing at getting rid of ads in every application imaginable - way before ABP became popular. It even stripped them from MSN somehow. People say that the more recent editions are actually good, but I just don't see the need to pay any more. If it was a mission critical computer, maybe, but it's not.