Like everyone else at the end of the 20th Century, I had a thing for calla lilies, and carried them in my wedding bouquet. My husband buys them for me every anniversary. My grandmother loved her climbing rose (too prickly!); my goddaughter prefers sunflowers over everything else.
But my favorite flowers are Spring bulbs: crocuses, daffodils, hyacinths, snowdrops, canas. They are easy to plant, easy to grow, and will divide on their own, and spread through the yard with some help from the squirrels, aka God's little gardeners. Winter ends and, without any work on my part, my yard is full of color.
Another of my spring favorites is rhubarb, which I've had middling success growing it and less success finding it at farmers' markets.