I don’t know how I’d never heard of this Firefox extension before today. Maybe it hasn’t been around long. It’s called Cute Menus. It puts these cute little icons next to items in the Firefox menus. There’s even one specifically for the Crystal SVG firefox theme.
I really like how it makes Firefox look. I installed at work today and right when I got home this evening. Below is a quick screenshot. To install, just visit the Cute Menus page on the Firefox extension repository.