My standard browser is Firefox 3 because of its rendering, cross-platform availability and mostly because of its extensions. Some time ago I installed Google Toolbar to be able to see the page rank of websites I visit. Since then, every new tab I open took much longer to load than previously - I had to wait entering the URL I really wanted to visit to allow Google Toolbar to render 9 screenshots of my "most visited" sites. Well that's nice and all Google, but I've got shortcuts for those sites and even if I don't, I could possibly type their URL faster than it takes you to display this rather useless page in every new tab I open. So I went on a quest to disable this function and it's actually not hard at all!
To disable the “most visited” pages in Firefox with Google Toolbar, simply: