I'm sorry she's overtaken Victoria. Victoria- or at least the image crafted of her by her spin doctors- stood for something. Elizabeth stands for nothing but continuity and the persistence of the "firm" she belongs to.
There was a fashion in the early years for talk about a New Elizabethan Age. Britten's Gloriana stands as a monument to that. It didn't last. It's not that there have been no great artistic or scientific achievements in her reign- just that none of them seem to have anything much to do with her. The first Elizabeth was surrounded by poets and pirates and magicians- all of them in some sense- working for her. She was- and made sure she was- at the heart of things. The second Elizabeth isn't. Her court- insofar as we have been allowed to glimpse it- smells of dogs and horses.
For someone who seems to have been painted every day of her life (a slight exaggeration) she'll leave few icons behind. Annigoni managed a couple of ultra-romantic early portraits. After that it was Rolf Harris all the way. I think the enduring image will be the one off the cover of the Sex Pistols album. Or perhaps- because it's worth so much in monetary terms- the portrait by Lucian Freud which shows her with a five o'clock shadow, looking grumpy.