I recommend
AdBlocker (which I believe is available for several different kinds of browsers across several different platforms). Also, the
Element Hiding Helper if you can get it, which allows you to block links and text and whole sections of pages. They're what I use, and I've been applying them especially heavily to YouTube lately. Also, if you're really getting ticked at certain kinds of advertising,
NoScript can really lay the smack down on anything AdBlocker and the Element Hiding Helper might have missed.