A:
Steve, it all depends on how big your boat is, what you're doing, and how many rods you want to own.
The 6' has an advantage in quick response and accuracy when you're in close. Generally a boat rod for vertical jigging and pitching in shallow. The 7' is more of an all around rod and one that will give you more casting distance, allow you to throw cranks, and will give you more line pickup on the hookset. Generally, the longer rod will have a more forgiving tip for rigging too. I would go for the 7' if you don't want to own both. I wouldn't worry about room in the boat when you're picking the rod though.