You can give the user the option to update quote on each opening/ with respect to time. And a faded button to copy the quote. Set background image of his own choice or use or default. It's a good and light weight extension. Best of luck.
The new quote on each opening.

Thanks for this Add-on! I like the quotes and the APOD image, but I don't like the Top Sites to be displayed as a list, if you could add a setting to show sites with thumbs (as in the default new tab) that would be great