Either a mini-nano-small Saint-Laurent (so many to to choose from) - or a Gucci.
For Gucci I would recommend the new Small Blondie top-handle which can worn cross-body for day and over the shoulder nonchalantly or in hand for more formal outfits/gatherings OR a Small Aphrodite. They all come in so many beautiful colours. You also have the option of Small or Mini Marmont in the Camera style, which can also look cool by day and chic at night.