I have over 300 sweet peas in pots waiting for planting out - there's nothing like them for colour and scent. I also love godetia and cosmos. I grow lots of flowers that make fantastic bouquets and cost a bomb in florists (if you can get them at all): malope, cerinthe, salpiglosis, eustoma (lisianthus), flax, cleome, tithonia, viscaria, moluccella, bupleurum, cosmidium, gaillardia. And things like night-scented stock and zalusianskaya that smell fantastic in the evening. It amazes me when people say annuals are too much trouble to grow.