It's interesting to see people's opinions on this as it seems to be quite varied. On facebook for example most people like the option where the camera is situated on the bottom right and also when I asked the same question on my stream most people preferred it on the right as well.
However there is also a large number of people that would prefer no webcam which I thought interesting. I personally believe a webcam is a great idea as it enables you to communicate with your viewers directly. It also adds personality and character which people can relate to. Anyway the amount of viewers for people who stream with webcams is generally always much higher than people who don't.