While I love gazanias, and plant some every year (although have never tried growing them from seed), my absolute favorite annual is lisianthus. My runner up would probably be zinnias, especially the bright colored ones like Wowie Zowie. I love almost anything that makes a good cutting flower.
Have you all noticed I am terribly lacking in the photo department? I will try to remedy that this season. You all have such beautiful images--I am in awe.