I am a firm believer in planting annual cutting flowers in your veggie garden. For one they are just beautiful. It is so nice to have a fresh picked floral arrangement no farther way than your tomatoes.
Secondly, they will entice humming birds and bees and other pollinators into your garden. Imagine looking up from your weeding to watch a humming bird flit between the flowers. This year I used my zinnias as sort of a distraction buffer between my hot peppers and my bell peppers to (hopefully) prevent any cross pollination. Seems to have worked well.