Personally, when it comes to clarity of thought, I've never found anyone who tops C.S. Peirce. He was unbelievably rational in his view of the world and of science and mathematics - he was scary. This is someone who recognized the fundamentally statistical nature of the sciences in the 1800's. He was able to see the broad philosophical implications of evolution in nearly as much clarity as many of your so-called "evolutionist" thinkers (can provide citation if requested).

A lot of people really admire Pierce, and I have trouble understanding why. It's very possible that hindsight bias makes me underestimate his ability, though. His Tychism seems confused and, AFAICT, he justifies it with a mind projection fallacy: "I can't predict this so it's fundamentally random". Also, he classified everything into groups of three so many of his good ideas were obsured by that weird numeralogical framework. Thirdly (heh), his theory of abduction seems to combine the generation and the assessment of hypotheses. Those processes are often done together and, indeed, it is usually most efficient to do them at the same time, but combining the two into a single process does not produce any deep insight into either.

Anyway, most of his other work seems good, I'm just probably having trouble understanding it in its historical context. His work on logic seems about on par with Frege, who I admire greatly for logic alone, so that's rather impressive, but Frege isn't praised the way Pierce is. You seem to be very familiar with Pierce though, so hopefully you can explain this to me.