What is the best bike for me?

I have not biked since I was 14. (I'm 26 now.) But, I would love to take it up this year. I would like to keep it recreational, no marathons or rocky terrains, just biking around my neighborhood and to the local book store. I'm not in terrific shape, so I would like something that will help me get some exercise, but not something that's so uncomfortable it will deter me from seeing out my goal. I'm a girl, not sure if that's pertinent. And, I am a very aesthetically minded person, so it's not real important, but if it's convenient I would like a bike that looks nice as well. I would like to spend less than 200 dollars, but for the perfect bike, I would be willing to dig deep and spend more. Any suggestions?