In my book, nothing quite beats a black velvet dress. I have acquired so many because it seems that each one I find is a tad bit different in some way. One's sleeveless, one's off the shoulder, one has a fuller skirt, one is above the knee but with long sleeves...oh, the list could go on and on. I have found them all at thrift stores, and they're always very reasonably priced (never over $10).
dress, umbrella - thrifted // shoes - H&M // hat - ASOS