Options - Gerneral - Browsing
autoscrolling
smooth scrolling
x hardware acceleration
check spelling
Tools - Addons - Extensions (ctrl-shift-a)
Firebug https://addons.mozilla.org/en-US/firefox/addon/firebug/
Youtube Video Downloader https://addons.mozilla.org/en-US/firefox/addon/youtube-video-and-audio-dow/
Filter: animate tabs.animate F panorama.animate_zoom F
Filter: newtab browser.newtabpage.enabled F