Two great add-ons make Firefox the best way to surf.
One is Flashblock 1.5.6
Flashblock is an extension for the Mozilla, Firefox, and Netscape browsers that takes a pessimistic approach to dealing with Macromedia Flash content on a webpage and blocks ALL Flash content from loading. It then leaves placeholders on the webpage that allow you to click to download and then view the Flash content.Flash can really slow you down, or worse automatically play noise and video when you arrive at a page. This kills everything. If you want to have flash play on your favorite pages you can "whitelist" those pages to allow flash to play.
Flashblock currently blocks the following content types:
* Macromedia Flash
* Macromedia Shockwave
* Macromedia Authorware
The other is Adblock Plus 0.7.5.5 which blocks banners and all sorts of ads including pop-ups, scrolling ads, etc.
Both are essential.