I wouldn't say I enjoy listening to anyone smart. It can be interesting to see what different people have to say, regardless of where their IQ puts them on the curve. Quite often I find that smart people celebrities such as the ones you mention only have insight to offer in one area and are pretty out of touch with life in the general population.

I would recommend picking multiple sources who are in a specific field/topic that you're interested in. Try to get opposing viewpoints.