Need some advise for landscaping

We are looking into planting some flowers this spring to fill this empty area in the flower bed. I'm not sure what I would like to plant. It needs to be something that can hold up for full sunlight all day. Does anyone have any suggestions? I want something with some color. I loved the flower in the photo above but I haven't been able to find out what kind of flower that is. I've also heard that the common marigold can add color and can also produce a smell that will deter any critters from having a sunday brunch in my flower beds. I can't have anything that produces too much scent as I am allergic to almost anything that blooms. I love to leave my windows open in the front of the house and it would fill my house with whatever scent it is... Any suggestions would be greatly appreciated.