Gentlemen: it may just be that you have no idea what to buy for that special lady in your life for Christmas. The last few December 25th dates may have been awkward as she rejected your gifts of impractical underwear, exotic food, cookware and/or cleaning equipment. She hasn't told you want she wants for this Christmas, and her hints haven't been heavy enough for you to notice.
She almost certainly wants shoes that she would feel guilty buying for herself. Go check her browsing history. Check her existing shoes of the same brand for appropriate size (and make sure you keep the receipt in case she needs to move up/down a size). That information should also give you a hint about appropriate colour. Extra points if you mention (when she unwraps the gift) that she might also want appropriate tights but you weren't sure, so would be happy to go shopping with her in the sales.
The above probably also applies if she's a Goth, though tights may not be required.
If you have absolutely no idea what kind of shoes she wants, but know that she likes "dressy" and doesn't have any foot problems, and you are willing to burn money for happiness, then head for the Louboutins.
No warranty is implied or given for this advice. Best of British luck.