Native to my area and flowers that I love are poppies, Jackob's ladder, peonies, daylily's (which can be boring unless you have many different colors), shrub roses (rosa rubrafolium is one I love), lilac, lily of the valley, bee balm, cone flower, coreopsis, silver mound, iris, and many more.
Oh wait you said favorite flower
That would have to be the beautifully fragrant flower of the Linden tree which blooms in June here in Maine. The flower is not elegant, white/off white star shaped blooms, but the frangrance is so intoxicating. I would compare it's strong scent to a gardenia, though they dont smell the same, it's just a powerful, and unique scent.