Your new tab page is obviously a pretty important part of the Firefox experience. Both Mozilla and Google have pretty slick options you can plug in, but you may not have heard of New Tab King yet.

Like other options, NTK taps into your recent usage to display frequently visited sites and recently closed tabs. You can toggle the display of your used sites to include either all browsing or only sites that are in your bookmarks. There's also a list of Windows shortcuts included for quick access to your My Documents folder, Notepad, Calculator, and Windows Media Player. You can also specify a custom background image.

And let's not forget about the boss mode button! Click it, and New Tab King automatically switches to a pre-defined display which includes sites like Harvard Business Publishing, Wall Street Journal, NASA, and the BBC ticker.

No, it won't destroy all traces of any questionable browsing you've been doing, but with boss mode on you can at least quickly shield your other tabs from prying eyes with control + t.

Edit: as noted by our commenters, this one is Windows only. The Firefox addon does state that, and while this post is tagged "windows" I didn't state that directly.