Well, obviously my favorite favorite annuals are zinnias. Like Jai, I have a few "other favorites" as well -- Portulaca (moss rose--they thrive on heat, but their seeds are a little small), snapdragons (our summers are a tad too hot for them, but they usually survive to bloom again in the Fall), and Nasturtiums (they make a nice snack and their seeds are big).
I like the look and color range of Petunias and their related Calibrachoas, but their seeds are just too small for me to mess with. The smaller seeds of the
Zinnia haageanas are also a little off-putting for me, although I can handle them OK. I prefer the larger seeds of "regular" zinnias.
ZM