Find a old good running Honsa Rebel 250 or 450. Ride it a summer to see if you like it and want to stay with it. And possibly depending on your size a Honda Shadow 1100. That are shaft drive, easy maintenance, and low center gravity.
All this talk about fit.... This is a bit of concern for me, as I'm only 5'9" 200lbs. Any good resources online or in the city of figuring out what is a proper fit? It's my understanding that it good to be able to flat foot at least one leg when at a stop, but that's all I have heard.