everyone's only got one thing to say

I'll admit that this is a bit subjective, and perhaps over simplified. But, in my view, everyone has basically one thing to say in their academic lives. My advice, based on this principle, is to (almost) never take more than one class from any given professor. Take one class, get the point, and move on to get someone else's point.

There's some really interesting faculty in planning schools and schools in related spheres such as geography, politics, economics, public health, statistics, law, etc. Expose yourself to as many different ones as you can.

I'd extend this advice by suggesting that you take as many classes outside your school as you can get away with and still graduate on time. Small schools (and many planning schools are small) tend to develop personalities that limit their perspectives on the world. In some sense, every school has only one thing to say ... get it and move on.

The down side of this advice is that you will encounter many faculty for whom you do not develop an appreciation. In every term, you must balance the benefit of taking (another) class from a professor you already know and like with that of risking that time slot on an unknown. I cannot put a pretty face on that decision point.