Anything very polished or dainty, including traditional classic (a la Coco Chanel). It ends up being much too high-maintenance for me.
I simply do not have the neat, regular features that would make it an effortless look, and lack the skills or time to groom myself into a semblance of it. Even if I were in the mood to try, my abilities with a straightening iron or curling wand are something to be seriously scared of. The compromise would be short hair, but then my relatively boyish face requires astounding amounts of grooming, make-up, accessorizing to prevent an all-out mannish appearance ---- which ends up an even worse mismatch for traditional feminine classic outfits! For the same reason, toning myself down to dainty is a lost battle even before I begin --- I may be petite, but I can only stay well-groomed enough to look 'dainty' for a few hours (and that's fewer hours than it took to get me there --- it's been tried!).
I've made my peace with my lack of polish, therefore. That said, as Angie pointed out, I can certainly edge in the direction of traditional classic feminine without going all the way there. There's just got to be room left for the rough edges of me, a la manicure-free hands and flyaway hair --- so make that more messy librarian and less classic Coco, let's say! But I would have to stop well short of the quilted patent-leather purse with the gold chain, to stay comfortable in my skin.